testing device for determining urine density, absorbent article, method for determining urine densit

专利摘要:
TESTING DEVICE TO DETERMINE URINE DENSITY, ABSORBENT ARTICLE, METHOD TO DETERMINE URINE DENSITY, AND RELATIVE URINE DENSITY MONITORING METHOD. The present invention describes a lateral flow testing device for determining the relative ionic strength of urine. The device includes a buffering zone having a polyelectrolyte disposed therein, and an indicator zone having a pH indicator immobilized non-diffusively therein, the indicator zone being separate from the buffering zone and positioned adjacent to, and in fluid communication with, a, buffer zone. A detection zone is part of the buffering zone, and features a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa (less than equal) 10-3, and a class of charged polymeric surfactants that respond to concentrations of relative ions in a sample solution, and a charged pH indicator with a charge opposite to that of the charged polymeric surfactant. The charged polymeric surfactant is soluble in amounts greater than or equal to about 1% by weight ((less equal) 1% by weight of solute) in water and in aqueous solutions of low ionic concentration of ((less equal) 0.1% by weight of (...).
公开号:BR112013003561B1
申请号:R112013003561-7
申请日:2011-07-25
公开日:2021-04-20
发明作者:Xuedong Song；Ning Wei；Ronnie L. Phillips
申请人:Kimberly-Clark Worldwide, Inc.；
IPC主号:

专利说明:

FIELD OF THE INVENTION
[001] The present invention relates to a dehydration sensor and absorbent products containing the sensor. In particular, the invention relates to a sensor that can monitor a user's hydration status. HISTORIC
[002] Dehydration is the depletion of fluids and associated electrolytes from the body. Typically, a person's total daily fluid amount is regulated to be within about ±0.02% of the body's weight, and the water in the body can comprise approximately 63% of the entire body mass. A balance of bodily fluids is achieved and maintained by correspondence to the intake and excretion of fluid from the body, and an imbalance in fluid can be linked to either dehydration or hypohydration. Dehydration can be of particular concern to each of the sick, elderly or children, and can have serious consequences for a dehydrated person if not properly cared for. Loss of body fluid in amounts of less than 25% of body mass has been associated with reduced heat dissipation, loss of cardiovascular function, and decreased physical endurance.
[003] The density of an individual's urine is a routinely measured means of assessing the individual's relative hydration status. Determining urine volume and electrolyte concentrations can help monitor whether the individual's body fluid amounts are in balance. Urine density (USG) refers to the ratio of urine density to water density. USG is mainly affected by solids and ions in urine. USG is proportionally correlated with the concentration of solids and the concentration of ions in the urine. The USG typically ranges from 1.002 to 1.030. It is accepted that USG < 1.020 is considered to be well hydrated, USG between 1.020 and 1.025 is considered to be semi-hydrated and USG > 1.025 is considered to be severely dehydrated. USG can be measured by an instrument such as either a urinal or dip sticks or urine test strips. Modern dip sticks are commonly based on lateral flow testing technology. Three main methods, namely refractometry, hydrometry and dipsticks, are commonly used for USG measurements. Although refractometry and hydrometry are very accurate, they require special instruments and people trained to operate them.
[004] Over the years, various manufacturers have tried different methods to improve the performance of dip sticks for density, such as different formulations to increase sensitivity and specificity. However, problems persist for all commercially available dip sticks. A major problem is that the user has to read a color change within a few short minutes after immersion in the sample, because the color development is not stable under the test conditions. Signals that can be observed outside the time window are often inaccurate, therefore, usually invalid. For some analyte tests, such as urine ion concentration (ie dehydration density), a certain period of time is required before a signal is fully developed and a valid reading can be obtained. This situation might not be an issue for a test that a user can constantly monitor; however, this becomes a problem when constant test monitoring is not feasible and sample introduction time is uncertain. For example, it is difficult, if not impossible, to accurately predict when an incontinent infant or adult will urinate to provide a sample for a testing device in a diaper or other personal care product. Therefore, the testing device needs a validation mechanism to ensure that a reading is within the valid reading time window.
[005] In recent years, reagent strips have become more popular, particularly in over the counter and point of care markets, mainly due to their low cost and ease of use. In general, conventional dipsticks change color in response to the ionic strength of a urine sample. Urine ionic strength is a measure of the amount of ions present in the urine. USG is proportional to the ionic strength of urine. Therefore, by testing the ionic strength of the test sample, USG can be determined indirectly and semi-quantitatively by correlating the ionic strength of urine to USG.
[006] Conventional reagent strips are usually made in such a way that all relevant reagents are diffusely immobilized together in a small porous zone on the strip. A urine sample is then applied to the zone or the entire tape is dipped into the urine sample and then removed quickly to allow color to develop. Examples of such reagent strips are described in U.S. Patent No. 4,318,709, to Falb, et al., and in U.S. Patent No. 4,376,825 to Stiso, et al.
US Patent No. 4,318,709, to Falb, et al., and US Patent No. 4,376,825 to Stiso, et al., both of which are hereby incorporated by reference, describe ion exchange chemistry of polyelectrolyte dye used in conventional test strips for measuring USG. In such conventional test strips, ions present in the urine induce an ion exchange with a polyelectrolyte, thereby introducing hydrogen ions into the urine. The change in hydrogen ion concentration is detected by a pH indicator.
[008] However, conventional reagent strips for measuring USG suffer from important drawbacks, particularly for the over-the-counter and point of sale markets. For example, conventional reagent strips have a limited read window because the signal produced by such strips starts to change only a short time after sample application. Signal change can be caused by reagent leaching (the result of diffusely immobilized reagents) and sample evaporation. Unless strips are analyzed shortly after sample application, the change in sign can lead to erroneous test results. In addition, because reagents on conventional strips are typically water soluble, strips must be removed quickly from the urine to prevent reagents from being leached into the sample. In addition, conventional dipsticks are often designed for only a single urine sample application. Multiple urine discharges can lead to erroneous test results making such tapes unsuitable for absorbent article applications where multiple urine discharges cannot be controlled. Finally, conventional dipsticks do not provide a way for a user to know if the test had been performed correctly or if enough sample had been applied.
[009] Although various types of dip sticks for dehydration have existed for many decades, existing technologies cannot meet the requirements for absorbent products. Some manufacturers of health and hygiene products wanted to broaden the appeal of their products to many consumers. These manufacturers have a long-standing desire to integrate dehydration sensors with absorbent products. This need has driven the development of low-cost dehydration sensors that can be integrated into an absorbent article such as a diaper or incontinence garment. However, prior lateral flow-based dewatering sensors, which are feasible for incorporation into absorbent products, are relatively complicated and economically inhibiting for integrating the sensors into each type of absorbent garment. Therefore, there is a demand for a testing device that can provide such security to caregivers in a cost-effective manner. SUMMARY OF THE INVENTION
[0010] The present invention relates to a membrane-free fluidic testing device or a dehydration sensor, which can be integrated into an absorbent personal care article. The dehydration sensor employs ion-responsive, charged polymeric surfactants both to immobilize oppositely charged indicators and to improve the wettability of the sensors. Charged polymeric surfactants are highly soluble in water, but will precipitate when in a buffered or high concentration salt solution of about 1% by weight or greater. The amount of surfactant loaded can be up to about 22% by weight. In other words, the polymeric surfactant exhibits decreasing solubility with increasing salt concentration in an aqueous solution.
[0011] Unlike conventional side flow based dehydrating devices, the polymeric surfactant and pH indicator can be printed or otherwise applied as a coating directly onto the active surface of the porous substrate. The demand for a separate film or membrane to immobilize the pH indicator, which many conventional side flow devices employ, is eliminated. Therefore, the present arrangement of the invention minimizes or eliminates a physical interface between the film membrane, which conventionally maintains the pH indicator and the underlying porous substrate, which conventionally supports the buffer components. Furthermore, the present invention can reduce the cost and simplify the process of manufacturing side flow sensors.
[0012] The dewatering sensor is formed by a first substrate with a porous matrix adapted to conduct lateral flow. The substrate includes a sample contact zone and a detection or indicator zone as part of a buffer pad, a feedback zone as part of a wicking pad located downstream of the detection zone. The detection zone features a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa<10-3 or 10-2, and a class of charged polymeric surfactants, which respond to relative ion concentrations in a solution of sample, and a pH indicator charged with a charge opposite to that of the charged polymeric surfactant. The charged polymeric surfactant is soluble in amounts greater than or equal to about 1% by weight (>1% by weight of solute) in water and in aqueous solutions of low ionic concentration of <0.1% by weight of salts, but insoluble (< 1% by weight of solute) in aqueous solution of high ionic concentrations of > 0.1% by weight of salts.
[0013] Dehydration sensors are much simpler and much cheaper to manufacture than previous designs. The present invention moves one step closer to the possibility of integrating a dewatering sensor into each type of absorbent product. Desirably, the dewatering sensor is formed from a single porous substrate. The advantage of a single integrated substrate is that there will be no interface or edge effects, which tend to arise in dewatering sensors that use different types of materials.
[0014] In other embodiments, a dehydration sensor feature can regulate or control sample flow and modulate the manifestation of test results to reduce or eliminate errors. The test device presents a first substrate with a porous matrix adapted to conduct lateral flow. The substrate features a sample contact zone, a detection zone, an observation-feedback zone, and a flow control zone located between the detection zone and the feedback zone. Each of the respective zones is in fluid communication with each other, either directly or indirectly. The flow control zone contains a separate discrete substrate, such as a membrane or film, which may have a different porosity gradient or have a variety of flow path or microchannel characteristics that help to regulate the progress of a volume of sample from one section of the substrate to another. A support member holds each of the zones together in an integrated device.
[0015] The detection zone can be part of a buffered pad located between the sample contact zone and the flow control zone, or, alternatively, the observation-feedback zone, which is part of an action pad capillary. The capillary action pad can additionally include a sample control-observation zone, which modifies color upon contact with a urine sample, regardless of urine density. The flow control zone regulates flow from a buffer pad to the capillary action pad. In some embodiments, the flow control zone may be part of the same substrate as the capillary action pad; but, in other embodiments, the flow control zone is at least part of a second substrate, which separates from the first substrate. The flow control zone features a porous membrane that bridges a gap between the buffer pad and the capillary action pad. A variety of flow control devices or mechanisms can be arranged between the detection zone and the sample feedback-observation zone, with regions that overlap with the flow control zone, to modulate or regulate the lateral flow of urine or from other fluids, as the fluid progresses from the first face or inner face deposition zone to the second face or outer face detection zone. The flow control zone regulates the amount of time it takes for a visual signal to develop and appear in the observation-feedback zone until the color transition in the sensing zone reaches color stability. Mechanisms can take the form, for example, of microchannels arranged in predetermined patterns and/or one or a number of different substrate densities. These mechanisms can be oriented parallel or orthogonal to the fluid flow path. The flow control zone regulates a predetermined time before a visual signal develops in the observation-feedback zone so that the color transition in the sensing zone achieves color stability.
[0016] In another aspect, the present invention also describes a method for quantitatively or semi-quantitatively determining the ionic strength, or density, of a urine test sample. The method includes providing a side flow device with a porous matrix in fluid communication with a pad or buffer zone and an indicator zone; introducing a test sample into a sample zone in said buffer pad, allowing said sample to penetrate through a detection zone to said flow control zone before developing a visual signal in an indicator zone or capillary action. The buffering zone, including a polyelectrolyte disposed therein, the indicator zone including a non-diffusively immobilized pH indicator therein, the indicator zone being separated from the buffering zone and in fluid communication with the buffering zone, the capable polyelectrolyte of an ion exchange with the ions in the urine, in order to add or reduce the hydrogen ions in the urine, the pH indicator capable of producing a signal corresponding to the change in the concentration of hydrogen ions in the urine. Polyelectrolytes can include partially neutralized weak acids and bases. The test sample is placed in contact with the fluidic medium of the lateral flow device to determine the ionic strength of the urine based on the signal produced by the pH indicator.
[0017] Alternatively, a method for testing the ionic strength of a urine sample is provided. The method involves: introducing a urine sample to a testing device as described above with a sample zone and a detection zone with a weak acid and/or a weak base, passing or allowing the urine to migrate through of a buffer pad, causing a color change of a pH indicator in said detection zone. In some modalities, urine is also passed through a flow control zone to regulate the time required for a visual signal to appear in a control zone-feedback of the capillary action pad, until a color transition in the zone detection achieves color stability.
[0018] In another aspect, the present invention also relates to an absorbent article incorporating a lateral fluidic testing device as described above for monitoring hydration-or dehydration and comprising: a first substrate with a porous matrix adapted to conduct lateral flow, the substrate having a sample contact zone, a detection zone, an observation-feedback zone and a flow control zone located between the detection zone and the feedback zone, each of the zones it is in fluid communication with each other, either directly or indirectly by an adjacent component. The absorbent article would be able to determine the ionic strength of urine. The article includes a substantially liquid-impervious layer, a liquid-permeable layer, an absorbent core positioned between the substantially liquid-impervious layer and the liquid-permeable layer, and a lateral flow tester integrated with the article and positioned in a manner such that the device is in fluid communication with urine when supplied by a user of the article. Examples of absorbent articles may include diapers, adult incontinence products or feminine or personal care products, absorbent pads for medical or hospital use.
[0019] Alternatively, the invention describes an insert for an apparel (e.g., underwear) or absorbent personal care product, the insert comprising a testing apparatus having: a side flow tape having a porous matrix in fluid communication with a buffer pad, capillary action pad and a flow control zone situated between said buffer pad and said capillary action pad, said flow control zone regulates an amount of time necessary for the development and appearance of a visual signal in a control-feedback zone of said capillary action pad until a color transition, in a detection zone of said tampon pad, reaches color stability.
[0020] Additional features and advantages of the present sensor or three-dimensional testing device and associated absorbent articles containing such a sensor will be described in the following detailed description. It is understood that the following general description and the following description of details and examples are merely representative of the invention, and are intended to provide an overview for understanding the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is a schematic representation of three quarters of a lateral flow testing device according to the present invention.
[0022] Figure 2 is a perspective view of one embodiment of an absorbent article according to the present invention.
[0023] Figure 3 is a schematic representation of numerous dehydration sensors and their respective color changes when reacted with synthetic urine samples, each at different densities. DETAILED DESCRIPTION OF THE INVENTION
[0024] The present invention is based on prior generations of lateral flow dehydration test devices, such as described in U.S. Patent Application No. 11/956428, the contents of which are incorporated herein by reference. In particular, the present invention provides a dehydration sensor, which has incorporated polymeric surfactants that respond to ions and charged.
[0025] In another aspect, the invention describes, in part, a testing device for the quantitative or semi-quantitative determination of the ionic strength of a urine test sample. The testing device includes a substrate or device adapted for lateral flow comprising a fluidic medium defining a buffering zone and a detection or indicator zone, the buffering zone including a polyelectrolyte disposed therein, the indicator zone including a pH indicator immobilized therein non-diffusively, the indicator zone being separated from the buffering zone and in fluid communication with the buffering zone, the polyelectrolyte capable of an ion exchange with urine ions, in order to add or reduce hydrogen ions in urine, the pH indicator capable of producing a signal corresponding to the change in the concentration of hydrogen ions in the urine. Polyelectrolytes can include partially neutralized weak polymeric acids and bases. The test sample is placed in contact with the fluidic medium of the lateral flow device to determine the ionic strength of the urine based on the signal produced by the pH indicator. The side flow tape features a porous matrix that allows fluid communication with the buffer pad, the capillary action pad, and may include a flow control zone located between the cap and capillary action pads. Section I - Buffer Paint with Ion Responsive and Charged Polymeric Surfactants
[0026] The present invention can satisfy the demand for a better and more stable dehydration sensor. According to the invention, the dewatering sensor is composed of a single integrated porous substrate (eg a piece of cellulosic pad or filter paper) with a coating of 1) a buffering component made of a weak acid or a partially neutralized weak base with a dissociation constant of less than or equal to about 10-2 (pKa value <10-2; desirably <10-3), 2) a charged polymeric surfactant, and 3) a charged pH indicator, which has a charge opposite to that of the polymeric surfactant. The buffering component, loaded surfactant and indicator are all deposited on the same surface of the porous substrate. (The charged polymeric surfactant can be adapted from similar materials as described in US Patent Nos. 7,456,117 B2, 7,157,389 B2, 6,960,371 B2 or 6,828,014 B2, the contents of which are incorporated herein by reference. ). The three components can be deposited at the same location together or at different locations on the porous substrate. The coating can be applied either to the entire surface of the substrate or to a limited, localized area of the surface. Coatings can be applied using conventional printing techniques.
[0027] The pKa of weak acid should be less than about 10-3, which allows the salt content in the urine sample to influence the balance between the salt form and the acid form. The pKa of the weak base should also be less than about 10-3, which allows the salt content in the urine to influence the balance between the protonated form and the base form. The weak acid or base in the buffer can be, for example, a weak polymeric acid (eg, poly(acrylic acid)), or a weak polymeric base (eg, polyimine). The pH indicator can be a dye or dye (Bromothymol Blue, Nitrazine Yellow, Neutral Red), the specific color change of which depends on pH. An important feature of the invention is the incorporation of an unusual class of polymeric surfactants, which are charged and respond to relative ion concentrations in solution. The charged polymeric surfactant plays a dual role, acting as an immobilizing agent and a wettability enhancing agent. Surfactants are soluble in water and in aqueous solutions of low ionic concentration, although insoluble in aqueous solutions of high ionic concentrations. Surfactants tend to be soluble in amounts greater than or equal to about 1% by weight (>1% by weight of solute), in pure water, and in aqueous solution of low ionic concentration (i.e., <0.1% by weight for salts), even if insoluble (ie, < 1% by weight of solute) in an aqueous solution of high ionic concentration (ie, > 0.1% by weight of salts). The sensor takes advantage of this unique property as a way to immobilize non-diffusively loaded indicators, while at the same time improving substrate wettability. Ordinary charged surfactants cannot perform this characteristic, because these types of surfactants are soluble in water over a wide range of ionic concentrations. For dehydration sensors, where a high concentration of a buffer is required, intensifying immobilization and wettability by the surfactant can be achieved, which significantly simplifies the manufacture and use of the sensors.
[0028] The surfactant can be cationic or anionic. For example, one can use SSB-6: poly[acrylic acid-butyl-co-acrylate-co-acrylate 2-ethylhexyl-co-2-acrylamido-propane sulfonate sodium], or OASIS "L7170": poly[methyl-co-[(2-acryloyloxy)ethyl]trimethylammonium chloride]). The amount of polymeric surfactant loaded can be from about 0.1 wt% to about 20 wt% or 22 wt%, but typically is between about 0.5 or 1 wt% to about 15 wt. or 17% by weight, more typically between about 1.5 or 3% by weight to about 10 or 12% by weight, and desirably between about 2 or 4% by weight to about 7 or 8% by weight. Particular embodiments, for example, can range from about 1-5% by weight.
[0029] Unlike previous generation side-flow-based dehydration sensors, a side-flow dehydration sensor in accordance with the present invention is configured to display all reagents deposited on the same single porous substrate, without the need of any interface between substrate with indicator immobilized on it and porous substrate with buffer on it. This structural configuration helps to promote good sample flow and reagent mixing. The dehydration sensor of the invention allows for dispensing with the use of an indicator pad and a feedback zone pad, as commonly employed in other dehydration sensors. Rather than employing charged membranes to immobilize the indicators for the sensing zone and the feedback zone, the new sensor uses charged polymeric surfactants to immobilize the oppositely charged indicators on a single integrated porous substrate with buffer components. Unlike previous generation dehydration sensors, which needed to use multiple interfaces, through which the liquid sample has to pass, before completing the test test, the current sensor does not present any interface that could interfere with the flow of liquid. As a result, the dewatering sensors of the present invention exhibit better performance in terms of consistency of results over many tests.
[0030] Additionally, whereas previous sensor designs required separate physical parts and required several steps to assemble the entire sensor device, current sensor fabrication is simplified and can be done through two general steps. First, provide a substrate with a porous matrix, or saturate with or deposit a sufficient amount of buffer solution components on top of the porous matrix, and allow the buffer coated substrate to dry. Then, secondly, apply a pH indicator and a loaded polymeric surfactant solution to the dry buffer coated substrate. The pH indicator and loaded polymeric surfactant can be printed or otherwise applied to the substrate, either together simultaneously or separately in series. When deposited together, the surface area of the substrate with the pH indicator must overlap with at least a portion of the area, which has the loaded polymeric surfactant applied, and vice versa. Furthermore, the devices' reduced materials and complexity make them much less expensive to make, which is an advantage for the widespread implementation of such sensors in many absorbent products in consumer use.
[0031] Examples of porous matrices include cellulose pads, filter papers, non-woven materials and fiberglass pads. A method for quantitatively or semi-quantitatively determining the phonic strength of a urine test sample, the method comprises: providing a lateral flow testing device having a porous medium defining a buffering zone and a detection zone or of bookmark. The porous matrix should not significantly interfere with the association and dissociation constant of the buffer. The dewatering tester features a test pad (zone) that does not non-diffusively immobilize with a pH indicator. The pH indicator desirably exhibits a color transition around neutral pH, or at a pH of about 5.5 to about 10.5. Examples of the pH indicator include Bromothymol Blue, Thymol Blue, m-Cresol Purple, Bright Yellow and Neutral Red. It is preferred that the matrix is porous and compatible with urine (aqueous) to allow for rapid penetration of urine.
[0032] The buffering zone including a polyelectrolyte disposed therein, the detection zone having a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa <10-2, and a class of charged polymeric surfactants, which respond to relative ion concentrations in a sample solution, and a pH indicator charged with a charge opposite to that of the charged polymeric surfactant, immobilized non-diffusively there. The buffer may consist of partially neutralized weak polymeric acid or base. Examples of weak polymeric acids or bases can include poly(acrylic acid), poly(maleic acid), poly(vinyl-amine) and poly(4-vinyl-pyridine). The buffer may consist of weak non-polymeric acids such as 2-(N-morpholin)-ethanesulfonic acid and bis-(amino-ethyl)-glycol-ether-N,N,N',N'-tetraacetic acid.
[0033] The dehydration sensor can be made by several simple methods. An example of preparing a dipstick dehydration sensor involves: applying a buffering solution of partially neutralized weak acids or bases (eg polymer bases are deposited onto a porous substrate such as a piece of cellulose pad or a piece of filter paper, and then drying the porous substrate). Typically, the buffering solution is an aqueous solution. An indicator solution, which contains one or more ion-responsive charged polymeric surfactants and one or more pH indicators, is deposited together onto the porous substrate and dried to prepare the final dip stick sensors. The indicator solution can be a solution containing water, volatile organic solvents or both. The amount of charged polymeric surfactant is at least twice that of the charged pH indicator in percent by weight. Alternatively, another example of manufacturing an immersion stick dehydration sensor involves: providing a buffer solution containing partially neutralized weak acids or bases and one or more charged polymeric surfactants that respond to ion and depositing the buffer solution onto an integrated single porous substrate and the drying of the porous substrate. An indicator solution, which contains one or more pH indicators, is deposited onto the porous substrate and dried to prepare the final dip stick sensors. The indicator solution can be a solution containing water, volatile organic solvents or both.
[0034] Several ways can be employed to prepare a dewatering sensor with a lateral flow format, in accordance with the present invention. According to an embodiment of the invention, one way is, for example, to first provide a porous substrate tape, such as cellulose pads or paper filters, and soak the substrate with a solution containing partially neutralized weak acids or bases and a or more charged polymeric surfactants that respond to ion and is dried. Then, an indicator solution containing one or more pH indicators loaded into the detection zone and/or an indicator into the feedback zone are simultaneously or separately deposited on the different positions of the porous substrate and the porous tape is then dried to prepare the side flow dewatering sensor. The sensor can then be additionally sealed in a detection and feedback zone to minimize sample evaporation.
[0035] The present invention helps to stably bind indicator molecules to the substrate surface and prevent them from being leached from the testing or observation sites projected onto the sensor. According to one embodiment, the sensor may take the form of a dip stick, but unlike conventional dip sticks for detecting dehydration, the indicator on the sensor will not leach from the substrate.
[0036] According to another example, a buffering solution of partially neutralized weak acids or bases is first deposited onto a porous substrate and the porous substrate is then dried. An immobilization solution, which contains the ion-responsive charged polymeric surfactants, is subsequently deposited onto the porous substrate and the substrate is dried again. Finally, an indicator solution, of the charged pH indicators, is deposited on the porous substrate and the substrate is dried. The substrate can be graded and cut into appropriately sized tapes to prepare the final dip stick sensors.
[0037] In another embodiment, unlike conventional dip sticks, which have only one detection zone, the dip stick dewatering sensor of the invention can be configured to have both a detection zone and a feedback zone . An advantage of having both of these zones together on a single substrate is that it lets the user know if the device has functioned properly and if the signal on the device has developed properly, or communicates whether enough urine sample had been applied to the device. The pH indicator in the detection zone displays different colors or different color intensities or different hues in response to the ionic strength of an analyte sample. The indicator in the feedback zone will show a color change once the sample is in contact with the sensor, regardless of its ionic strength. The simple permanent immobilization of the ion-responsive charged polymeric surfactant makes this possible.
[0038] When manufacturing the sensor, for example, a buffering solution of weak partially neutralized acids or bases can be deposited on a porous substrate and the porous substrate is dried. Next, an immobilization solution, which contains the ion-responsive charged polymeric surfactants, is deposited on the porous substrate and the porous substrate is dried. A pH indicator solution, of the charged pH indicators, is then deposited at a first predetermined location on the porous substrate, to a detection zone, and another charged indicator solution is deposited at a second predetermined location on the porous substrate, to make a feedback zone. The two predetermined locations are separate, distinct and/or remote from each other. The substrate is allowed to dry before preparing the final sensors. Section II - Lateral Flow Format for Dehydration Monitoring
[0039] Conventional urine testing devices, such as dip sticks or test strips, operate by immersing the dip stick in a urine sample and withdrawing it quickly, and then reading the resulting color , which can be compared with a color scale. Typically, these test tapes have a short read window, typically about two minutes or less, and have no user feedback mechanism. Unlike previously developed lateral flow hydration test formats, the hydration testing and monitoring device according to US Patent Application No. 11/956428 features a reading window with a much longer duration of at least about 2 hours, typically about 4-6 hours or more, with stable color signal and a user feedback zone, to indicate a sample volume and sample contact with the test zone. The extended read window and long-term stability of the color signal and the user feedback mechanism are important features for an over-the-counter (OTC) test format, in particular, for a test on a personal care product, where constant monitoring is not practical.
[0040] No currently available external dewatering sensing technology can provide a feasible solution for consumer-use absorbent products. Previous generation dewatering sensors, based on a lateral flow format, can be integrated into an absorbent product by providing a stable signal and a feedback mechanism. Although that type of sensor is relatively inexpensive to manufacture (less than about 5 cents per device) and is feasible to put into an absorbent product, such as an insert on a necessary basis, the cost is still too high to use. general with each type of absorbent product for personal care for the consumer. In order to reduce the cost of the sensor, a dewatering sensor that is much simpler and much cheaper is needed. Such a sensor can be achieved by means of a new immobilization and wetting technique.
[0041] The present invention provides an improved lateral flow assay device and format for monitoring urine density. The present invention builds on, and advances beyond, the development of prior hydration sensors, such as described in U.S. Patent Application Publication No. 2009/0157024, the contents of which, in its entirety, are incorporated herein by reference.
[0042] Urine density (USG) can be used to indicate the presence or degree of dehydration in human subjects. Since urine density is correlated with urine ionic strength, urine ionic strength measurements can be used to estimate density in devices screening for the presence or severity of dehydration.
[0043] In this regard, the present invention is generally directed to a lateral flow testing device for determining the ionic strength of urine. The device may include a buffering zone with a polyelectrolyte disposed therein, and an indicator zone with a pH indicator immobilized non-diffusively therein.
[0044] Non-diffusive immobilization of the pH indicator can greatly extend the period of time that the signal for phonic strength remains stable. In addition, physical separation of certain reagents can reduce the impact of any sample loss or diffusion over time on the pH fluctuation around the pH indicator.
[0045] In certain embodiments, the coating material may cover at least a portion of the buffering zone and a portion of the indicator zone, so as to avoid exposing such covered portions to the outside environment. The coating material can minimize sample evaporation and can also limit reagent exposure to test device users. Additionally, in certain modalities, a control zone may also be present to provide users with an indication that the test had been performed correctly.
[0046] The devices described here provide a simple, cost-effective, user-friendly approach to rapid measurement of hydration status through urine. Additionally, the devices described herein can be incorporated into absorbent articles, such as diapers and incontinence pads, to aid in the determination of USG.
[0047] Referring to Figure 1, an embodiment of a lateral flow device 20, which may be formed in accordance with the present invention, will now be described in greater detail. As shown, device 20 contains a chromatographic medium 23 optionally supported by a rigid support material 21. In general, the chromatographic medium 23 can be made from any of a variety of materials, from which urine is capable. to pass. For example, the chromatographic medium 23 can be a porous membrane formed from naturally occurring or synthetic materials such as polysaccharides (for example, cellulose materials such as paper and cellulose derivatives such as cellulose acetate and nitro- cellulose); polyether sulfone; polyethylene; nylon; poly(vinylidene fluoride) (PVDF); polyester; polypropylene; silica; inorganic materials such as deactivated alumina, diatomaceous earth, MgSO4 or other finely divided inorganic material evenly dispersed in a porous polymer matrix, with polymers such as vinyl chloride, vinyl chloride-propylene copolymer and vinyl chloride-acetate copolymer vinyl; fabric, either naturally occurring (eg cotton) or synthetic (eg nylon or rayon); porous gels such as silica gel, agarose, dextran and gelatin; polymeric films such as polyacrylamide; and so on. In a particular embodiment, the chromatographic medium 23 is formed from a Biodyne.RTM.Plus membrane manufactured by Pall Corporation.
[0048] The size and shape of the chromatographic medium 23, in general, may vary as readily recognized by those skilled in the art. For example, a porous membrane tape can be from about 10 to about 100 millimeters in length, in some embodiments from about 20 to about 80 millimeters, and in some embodiments from about 40 to about 60 millimeters. . The width of the membrane tape can also range from about 0.5 to about 20 millimeters, in some embodiments, from about 1 to about 15 millimeters, and, in some embodiments, from about 2 to about 10 millimeters. . The thickness of the membrane tape may be less than about 500 micrometers, in some embodiments less than about 250 micrometers, and in some embodiments less than about 150 micrometers.
[0049] As mentioned above, support 21 carries chromatographic medium 23. For example, support 21 can be positioned directly adjacent to chromatographic medium 23 as shown in Figure 1, or one or more intervening layers can be positioned between the chromatographic medium 23 and support 21. Independently, support 21, in general, can be formed from any material capable of carrying the chromatographic medium 23. Furthermore, in general, it is desired that support 21 is impervious to liquids. so that fluid flow through means 23 does not leak through support 21. Examples of suitable materials for the support include, but are not limited to, glass; polymeric materials such as polystyrene, polypropylene, polyester (e.g. Mylar.RTM film), polybutadiene, poly(vinyl chloride), polyamide, polycarbonate, epoxides, methacrylates and polymelamine; and so on. To provide sufficient structural support for the chromatographic medium 23, the support 21 is generally selected to have a certain minimum thickness. Therefore, for example, support 21 may have a thickness ranging from about 100 to about 5,000 micrometers, in some embodiments from about 150 to about 2,000 micrometers, and in some embodiments from about 250 to about 1000 micrometers. For example, a suitable membrane tape having a thickness of about 125 micrometers can be obtained from Millipore Corp., of Bedford, Mass., under the name "SHF180B25".
[0050] As is well known in the art, the chromatographic medium 23 can be poured over the support 21, and the resulting laminate can be die-cut to the desired size and shape. Alternatively, the chromatographic medium 23 can simply be laminated to the backing 21 with, for example, an adhesive. In some embodiments, a porous nitrocellulose or nylon membrane is adhered to a Mylar.RTM film. An adhesive is used to bond the porous membrane to the Mylar.RTM film, such as a pressure sensitive adhesive. Laminate structures of this type are believed to be commercially available from Millipore Corp. of Bedford, Mass., USA. Still other examples of suitable laminated device structures are described in U.S. Patent No. 5,075,077, to Durley, III, et al., which is incorporated herein in its entirety by reference thereto for all purposes.
[0051] To begin measuring the ionic strength of urine, a user can directly apply the test sample to a portion of the chromatographic medium 23, through which it can then transition in the direction illustrated by the arrow "L" in Figure 1 Alternatively, the test sample may first be applied to a sample application zone 24 which is in fluid communication with the chromatographic medium 23. As shown in Figure 1, the sample application zone 24 can be formed in the middle 23. Alternatively, the sample application zone 24 can be formed of a separate material, such as a pad. Some suitable materials that can be used to form such sample pads include, but are not limited to, nitrocellulose, cellulose, porous polyethylene pads and fiberglass filter paper. If desired, the sample application zone 24 can also contain one or more pretreatment reagents, diffusely or non-diffusively attached thereto.
[0052] In the illustrated embodiment, the test sample transitions from the sample application zone 24 to a buffer zone 22, which is in communication with the sample application zone 24. As shown in Figure 1, the buffer zone 22 may be formed in middle 23. Alternatively, the buffer zone 22 is formed of a separate material or pad. Such a buffer pad can be formed from any material through which the test sample is able to pass, such as glass fibers or other such materials already described herein. It should also be understood that the sample application zone 24 can be defined as part of the buffer zone 22.
[0053] To facilitate the measurement of the ionic strength of urine, in the manner described above, a polyelectrolyte is disposed, at a certain pH, in the buffering zone 22. In some embodiments, the polyelectrolyte can be immobilized in a diffusive manner in the buffering zone 22 of device 20, prior to application of the test sample. The polyelectrolyte can be disposed downstream of the sample application zone 24. In this way, the urine sample is able to mix with the polyelectrolyte upon application. Alternatively, the polyelectrolyte can be positioned upstream of the sample application zone 24. For example, a diluent can be employed to induce mixing between the polyelectrolyte and the test sample. In this way, the urine sample is able to mix with the polyelectrolyte upon application.
[0054] As described above, ions present in urine induce an ion exchange with the polyelectrolyte, thereby adding or reducing hydrogen ions in the urine. In that regard, a polyelectrolyte can include a polymeric acid or a polymeric base, particularly weak polymeric acids and weak polymeric bases. Weak polymeric acids or bases change their apparent association/dissociation constants with the changing ionic strength of their environments. For example, when the concentration of cations increases, the dissociation constant of a weak acid based on carboxylic acid increases to release more protons to increase the acidity of the solution.
[0055] The selection of buffer components can be important for measuring the sensitivity threshold and color change of the device. In certain embodiments, the buffer system is preferably a partially neutralized weak polymeric acid or a partially neutralized weak polymeric base. In this regard, the association constants or the apparent dissociation constants of the acids or bases used must be sufficiently sensitive to ionic strength. There are a number of suitable weak polymeric acids and bases that can be used with the present invention. For example, useful weak polymeric acids may include poly(acrylic acid), poly(maleic acid), maleic acid-vinyl methyl ether copolymer, poly(methacrylic acid), styrene-maleic acid copolymer, and maleic anhydride-methyl vinyl copolymer ether. Useful weaker polymeric bases can include poly(vinyl-amine) and poly(4-vinyl-pyridine). However, it should be understood that any suitable polyelectrolyte is contemplated by the present invention.
[0056] In certain embodiments, polymeric acids or bases can be neutralized by at least 50% to make an effective sensitive buffer. The initial pH of the buffer can usually be adjusted to a certain range so that the threshold density color changes can be tailored to some degree. For example, the threshold detection of USG is slightly higher when the pH of the starting buffer is higher and when a weak, partially neutralized polymeric acid is used. However, adjustments can be limited by the intrinsic association/dissociation constants of the acids or bases used. The color transition threshold can also be adjusted by using different buffer components. For example, a significant color change occurs around 1.020 USG for poly(vinyl chloride-co-vinyl acetate-co-maleic acid), while the threshold transition point is around 1.010 for poly(acid acrylic), when both buffers have an initial pH of 7.95.
[0057] Referring again to Figure 1, the lateral flow device 20 includes an indicator zone 31, within which a pH indicator is immobilized non-diffusively. Indicator zone 31 is separate from tampon zone 22, but positioned adjacent to, and in fluid communication with, tampon zone 22. Alternatively, indicator zone 31 may be formed of a separate material, such as a pillow. Some suitable materials that can be used to form such sample pads include, but are not limited to, nitrocellulose, cellulose, porous polyethylene pads, and fiberglass filter paper. In that regard, indicator zone 31 is further positioned adjacent to, and in fluid communication with, buffer zone 22.
[0058] The pH indicator can be applied directly to medium 23 or first formed into a solution before application. Various solvents can be used to form the solution, such as, but not limited to, acetonitrile, dimethyl sulfoxide (DMSO), ethyl alcohol, dimethylformamide (DMF) and other polar organic solvents. The amount of the pH indicator in the solution can range from about 0.001 to about 100 milligrams per milliliter of solvent, and, in some embodiments, from about 0.1 to about 10 milligrams per milliliter of solvent. In a particular embodiment, the indicator zone 31 is defined by the chromatographic means 23 and formed by coating a solution onto it, using well known techniques, and then drying. The pH indicator concentration can be selectively controlled to provide the desired level of sensitivity detection.
[0059] It is desired that the pH indicator be applied in such a way that it does not substantially diffuse through the matrix of the chromatographic medium 23 (i.e., immobilized non-diffusively). This allows a user to readily detect the color change that occurs when the pH indicator reacts with urine, and also prevents the pH indicator from being removed by leaching from the indicator zone 31. Immobilization can be achieved by many methods such as chemical bonding, physical absorption or using a vehicle such as a polymer or a particle. In a preferred embodiment, a highly charged porous material can effectively immobilize an oppositely charged indicator. In that regard, useful loaded porous substrates can include nylon membranes, such as Biodyne.RTM.Plus, from Pall Corporation. Porous non-woven materials such as tissue papers treated with Kymene.RTM have also been considered to be charged materials suitable for immobilizing negatively charged indicators.
[0060] In certain embodiments of the present invention, a reticulated network containing the pH indicator is formed in a chromatographic medium of a lateral flow device. Without wishing to be bound by theory, it is believed that the reticulated network can help to durably secure the pH indicator, thereby allowing a user to more readily detect a change in its color during use. The crosslinked network may contain "intra-crosslinked bonds" (i.e., covalent bonds between functional groups of a single molecule) and/or "cross-linked bonds" (i.e., covalent bonds between different molecules, for example, between two pH indicator molecules or between a pH indicator molecule and the substrate surface). Crosslinking can be carried out via self-crosslinking of the indicator and/or through the inclusion of a separate crosslinking agent. Suitable crosslinking agents, for example, may include poly(glycidyl ethers), such as ethylene glycol diglycidyl ether and poly(ethylene glycol) diglycidyl ether; acrylamides; compounds containing one or more hydrolyzable groups, such as alkoxy groups (for example, methoxy, ethoxy and propoxy); alkoxy-alkoxy groups (for example, methoxy-ethoxy, ethoxy-ethoxy and methoxy-propoxy); acyloxy groups (for example acetoxy and octanoyloxy); ketoxime groups (for example, dimethyl-ketoxime, methyl-ketoxime and methyl-ethyl-ketoxime); alkenyloxy groups (e.g., vinyloxy, isopropenyloxy and 1-ethyl-2-methyl-vinyloxy); amino groups (for example, dimethyl-amino, diethyl-amino and butyl-amino); aminooxy groups (for example, dimethyl-aminooxy and diethyl-aminooxy); and amide groups (for example, N-methyl-acetamide and N-ethyl-acetamide).
[0061] Any one of a variety of different crosslinking mechanisms can be employed in the present invention, such as thermal initiation (eg condensation reactions, addition reactions, etc.), electromagnetic radiation, and so on. Some suitable examples of electromagnetic radiation, which can be used in the present invention, include, but are not limited to, electron beam radiation, natural and artificial radioisotopes (e.g., α, β and y rays), X-rays, electron beams. neutrons, positively charged beams, laser beams, ultraviolet, etc. Electron beam radiation, for example, involves the production of electrons accelerated by an electron beam device. Electron beam devices, in general, are well known in the art. For example, in one embodiment, an electron beam device can be used, which is available from Energy Sciences, Inc., of Woburn, Mass., USA, under the name Microbeam LV. Other examples of suitable electron beam devices are described in U.S. Patent No. 5,003,178 to Livesay; in U.S. Patent No. 5,962,995 to Avnery; in U.S. Patent No. 6,407,492 to Avnery, et al., which are incorporated herein in their entirety by reference thereto for all purposes. The wavelength, y, of the radiation can vary for different types of radiation in the electromagnetic radiation spectrum, such as from about 10-14 meters to about 10-5 meters. Electron beam radiation, for example, has a wavelength, y, of about 10-13 meters to about 10-9 meters. In addition to selecting the wavelength, y, of the electromagnetic radiation, other parameters can also be selected to control the degree of crosslinking. For example, the dosage can range from about 0.1 Megarads (Mrads) to about 10 Mrads, and, in some embodiments, from about 1 Mrad to about 5 Mrads.
[0062] The electromagnetic radiation source can be any radiation source known to those skilled in the art. For example, an excimer lamp or a mercury lamp with a D-bulb can be used. Other specialty doped lamps, which emit radiation at a fairly narrow emission peak, can be used with photoinitiators, which have an equivalent absorption maximum. For example, the V-bulb, available from Fusion Systems, is another suitable lamp for use. In addition, specialty lamps featuring a specific emission band can be manufactured for use with one or more specific photoinitiators.
[0063] Initiators can be used in some modalities, which enhance the functionality of the selected crosslinking technique. Thermal initiators, for example, can be employed in certain embodiments, such as azo, peroxide, persulfate and redox initiators. Representative examples of suitable thermal initiators include azo initiators such as 2,2'-azobis (2,4-dimethyl-valeronitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis-2-methyl-butyronitrile , 1,1'-azobis (1-cyclohexane-carbonitrile), 2,2'-azobis (methyl isobutyrate), 2,2'-azobis (2-amidino-propane) dihydrochloride and 2,2'- azobis (4-methoxy-2,4-dimethyl-valeronitrile); peroxide initiators such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di(4-t-butyl-cyclohexyl peroxydicarbonate), diethyl peroxydicarbonate (2-ethylhexyl), t-butyl peroxy pivalate, t-butyl peroxy-2-ethylhexanoate and dicumyl peroxide; persulfate initiators such as potassium persulfate, sodium persulfate and ammonium persulfate; redox (oxidation-reduction) initiators, such as combinations of the above persulfate initiators with reducing agents, such as sodium metabisulfite and sodium bisulfite, systems based on organic peroxides and tertiary amines, and systems based on organic hydroperoxides and metals of transition; other initiators such as pinacols; and the like (and mixtures thereof). Azo compounds and peroxides are generally preferred. Photoinitiators may also be employed, such as substituted acetophenones, such as benzyl dimethyl ketal and 1-hydroxy-cyclohexyl-phenyl-ketone; substituted alpha-ketols such as 2-methyl-2-hydroxy-propiophenone; benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether; substituted benzoin ethers such as anisoin methyl ether; aromatic sulfonyl chlorides; photoactive oximes; and so on (and mixtures thereof). Other suitable photoinitiators can be described in U.S. Patent No. 6,486,227 to Nohr, et al. and in U.S. Patent No. 6,780,896 to MacDonald, et al.; both of which are incorporated herein by reference.
[0064] Although not necessary, additional components can also be employed within the reticulated network to facilitate the fixing of the pH indicator. For example, an anchoring compound can be employed, which binds the pH indicator to the surface of the chromatographic medium and further improves the durability of the pH indicator in the side flow device. Typically, the anchoring compound is larger in size than the pH indicator, which improves the likelihood of remaining on the surface of the chromatographic medium during use. For example, the anchoring compound can include a macromolecular compound, such as a polymer, oligomer, dendrimer, particle, etc. Polymeric anchoring compounds can be natural, synthetic or combinations thereof. Examples of natural polymeric anchor compounds include, for example, polypeptides, proteins, DNA/RNA and polysaccharides (for example, glucose-based polymers). Examples of synthetic polymeric anchor compounds include, for example, poly(acrylic acid) and poly(vinyl alcohols). A particular example of a polysaccharide anchoring compound is activated dextran. In some embodiments, the anchoring compound can be a particle (which is sometimes referred to as a "bead" or "microbead"). Naturally occurring particles such as nuclei, mycoplasma, plasmids, mammalian cells (eg erythrocyte ghosts), unicellular microorganisms (eg bacteria), polysaccharides (eg agarose), etc. can be used . Furthermore, synthetic particles can also be used. For example, in one embodiment, latex microparticles are used. Although any synthetic particle can be used, the particles are typically formed from polystyrene, butadiene-styrenes, styrene-acrylic-vinyl terpolymer, poly(methyl methacrylate), poly(ethyl methacrylate), styrene-maleic anhydride copolymer, poly(vinyl acetate), poly(divinyl-benzene), poly(butylene terephthalate), acrylonitrile, vinyl chloride-acrylates, and so on, or an aldehyde, carboxyl, amino, hydroxyl or hydroxy derivative. hydrazide from them. When used, the shape of the particles in general can vary. In a particular embodiment, for example, the particles are spherical in shape. However, it should be understood that other formats are also contemplated, such as plates, rods, discs, bars, tubes, irregular shapes, etc. In addition, particle size may also vary. For example, the average size (eg diameter) of particles can range from about 0.1 nanometers to about 1,000 micrometers, in some embodiments, from about 0.1 nanometers to about 100 micrometers, and in some modes, from about 1 manometer to about 10 micrometers.
[0065] The manner in which the anchoring compound is used to link the pH indicator and the chromatographic medium may vary. In one embodiment, for example, the anchoring compound is fixed to the pH indicator before both are applied to the chromatographic medium. In other embodiments, the anchoring compound can be attached to the chromatographic medium prior to application of the pH indicator. In still other embodiments, the materials can be applied as separate components to the chromatographic medium and fixation reactions can optionally take place in situ at the same time as the crosslinking of the network. For example, the pH indicator can bind to the anchoring compound, the anchoring compound can bind to the medium, and simultaneously crosslinking reactions can take place between anchoring compounds, between indicators or between the two. In such an embodiment, the reticulated network thus formed can be physically maintained on the porous membrane of the chromatographic medium without the need for a connection between the porous membrane and the other components of the system. In particular, the latticework, portions of which may extend into and between the pores of the porous membrane, can be physically constricted in the membrane, even without specific bonds forming between the membrane and the components of the latticework.
[0066] In the case of bonds being formed between the system components, the fixation of the anchoring compound to a chromatographic medium, as well as the fixation of the anchoring compound to the indicator, can be performed using carboxylic, amino, functional groups, of aldehyde, bromoacetyl, iodoacetyl, thiol, epoxy or other reactive functional groups, as well as residual free radicals and radical cations, by which a binding reaction can be carried out and according to any methods suitable, for example, thermal processes, photoinitiated processes, catalyzed reactions, and the like. For example, a chromatographic medium can be amine functionalized by contacting an amine-containing compound, such as 3-amino-propyl-triethoxy-silane, to increase surface amine functionality and attach the anchor compound to the surface via, for example, aldehyde functionality of the anchoring compound. A surface functional group can also be incorporated into a particle-type anchoring compound as a reactive functionality, for example, when the surface of the particle contains a relatively high surface concentration of polar groups. In certain cases, the particle may be able to direct binding to a chromatographic medium and/or a pH indicator without the need for further modification.
[0067] It should be understood that, in addition to covalent bonding, other fixation techniques, such as charge-charge interactions, can also be used for the fixation of the anchor compound to the chromatographic medium and/or for the fixation of the pH indicator to the anchoring compound. For example, a charged anchoring compound, such as a positively charged polyelectrolyte anchoring compound, can be immobilized on a negatively charged chromatographic medium, such as a negatively charged porous nitrocellulose membrane, through charge-charge interactions between the two . Similarly, a negatively charged indicator, such as a diazonium ion, can be immobilized on a positively charged anchoring compound.
[0068] It is important to select a pH indicator that exhibits sensitivity to subtle buffer pH change caused by the ionic strength of urine. Since the pH of normal urine is around the neutral value, it is preferred that the indicator shows a significant color transition around the neutral pH of 7.
[0069] For example, in certain embodiments, phthalein chromogens constitute a suitable pH-sensitive class of chromogens that can be employed in the arrangement of the present invention. Phenol Red (ie, phenol-sulfone-phthalein), for example, exhibits a yellow to red transition over the pH range of 6.6 to 8.0. Above a pH of about 8.1, Phenol Red takes on a bright pink (fuchsia) color. Phenol Red Derivatives may also be suitable for use in the present invention, such as those substituted with chlorine, bromine, methyl, sodium carboxylate, carboxylic acid, hydroxyl and amine functional groups. Exemplary Substituted Phenol Red Compounds include, for example, Metacresol Purple (meta-cresol-sulfone-phthalein), Cresol Red (ortho-cresol-sulfone-phthalein), Pyrocatechol Violet (pyrocatechol-sulfone-phthalein), Red of Chlorophenol (3',3"-dichloro-phenol-sulphone-phthalein), Xylenol Blue (the sodium salt of para-xylene-sulphone-phthalein), Xylene Orange, Mordent Blue 3 (CI 43820), 3, 4,5,6-tetrabromo-phenol-sulfone-phthalein), Bromoxylenol Blue, Bromophenol Blue (3',3",5',5"-tetrabromo-phenol-sulfone-phthalein), Bromochlorophenol Blue (the salt 5',5"-dichloro-phenol-sulfone-phthalein sodium solution), Bromocresol Purple (5',5"-dibromo-ortho-cresol-sulfone-phthalein), Bromocresol Green (3',3" ,5',5"-tetrabromo-ortho-cresol-sulfone-phthalein), and so on. Still other suitable phthalein chromogens are well known in the art, and may include Bromothymol Blue, Thymol Blue, Bromocresol Purple, thymophthalein and phenolphthalein (a component common use of universal indicators). For example, Bromothymol Blue exhibits a yellow to blue transition over a pH range of about 6.0 to 7.6; thymophthalein exhibits a colorless to blue transition over a pH range of about 9.4 to 10.6; phenolphthalein exhibits a colorless to pink transition over a pH range of about 8.2 to 10.0; Timol Blue exhibits a first red to yellow transition over a pH range of about 1.2 to 2.8 and a second yellow to blue transition over a pH range of about 8.0 to 9.6; Bromophenol Blue exhibits a yellow to violet transition over a pH range of about 3.0 to 4.6; Bromocresol Green exhibits a yellow to blue transition over a pH range of about 3.8 to 5.4; and Bromocresol Purple exhibits a yellow to violet transition over a pH range of about 5.2 to 6.8.
[0070] A flow control zone can also be incorporated, which regulates the sample flow between the buffer pad and the capillary action pad. The flow control zone is capable of regulating the length of time the sample is in full contact with a buffer pad detection zone, and allows the test reaction to reach a stable signal before the development and appearance of a visual signal in a control-feedback zone of the capillary action pad. The detection zone can use a pH indicator that displays a color change that responds to different pH levels. The sample feedback-observation zone features a non-diffusively immobilized pH indicator and a pH adjuster. The pH indicator exhibits a color transition upon contact with the urine sample. The flow control zone features a porosity gradient differential relative to the adjacent buffer pad or capillary action pad. The flow control zone can be fabricated from a variety of materials, such as a nitrocellulose membrane, fiberglass pad, nylon membrane, cellulose pad, filter paper, non-woven material or polymeric film. .
[0071] In certain embodiments, the initial color of the immobilized indicator can be easily adjusted by immobilizing the indicator in conjunction with a pH adjuster, or an acid, a buffer, a base or some combination thereof. The starting color is important to provide as great a sharp color contrast as possible. For example, when Bromothymol Blue is used as an indicator, basic condition gives the indicator zone a vivid green color, which is clearly distinguishable from yellow color under slightly acidic condition.
[0072] Another zone, which can be employed in the lateral flow device 20 to improve the accuracy of detection, is a control zone 32. The control zone 32 provides a signal to the user that the test is working in an appropriate manner. appropriate. A control forming color is developed on the device downstream of the indicator zone. In certain embodiments, a control indicator is immobilized in the control zone in conjunction with a pH adjuster to result in an initial pH outside the typical pH range for a urine sample. In certain embodiments, such a range may include <5.5 or >9.5. The control indicator produces an initial color under the initial pH. Once the urine sample passes through the indicator zone and migrates to the control zone, the pH in the control zone changes to induce a color change for the control indicator, signaling that enough sample has passed through the indicator zone to the control zone and that the test had been done correctly.
[0073] Suitable control indicators, which can be used in control zone 32, include the pH indicators previously described here. Additionally, other suitable pH adjusters may include sulfonic acids (eg 2-[N-morpholino]ethanesulfonic acid ("MES"), carboxylic acids and polymeric acids. Specific examples of suitable carboxylic acids are citric acid, glycolic acid, acid lactic acid, acetic acid, maleic acid, gallic acid, malic acid, succinic acid, glutaric acid, benzoic acid, malonic acid, salicylic acid, glycolic acid and mixtures thereof Specific examples of suitable polymeric acids include chain poly(acrylic acid) linear and its copolymers (eg maleic-acrylic, sulfonic-acrylic and styrene-acrylic copolymers), cross-linked poly(acrylic acids) having a molecular weight less than about 250,000, poly(methacrylic acid) and naturally occurring polymeric acids , such as carrageenic acid, carboxy-methyl-cellulose, and alginic acid. Again, the pH adjuster results in an initial pH outside the typical pH range for uri na (or < 5.5 or > 9.5), whereby the control indicator produces a signal.
[0074] The location of control zone 32 may vary based on the nature of the test being performed. In the illustrated embodiment, for example, the control zone 32 is defined by the chromatographic means 23 and positioned downstream of the indicator zone 31. Alternatively, the control zone 32 may be formed of a separate material, such as a pad as described herein. with respect to the buffer zone and the detection or indicator zone.
[0075] Regardless of the particular control technique selected, application of a sufficient volume of urine to device 20 will cause it to form a signal within control zone 32, regardless of the USG. Among the benefits provided by such a control zone is that the user is informed that a sufficient volume of the test sample has been added without requiring careful measurement or calculation. This provides the ability to use the side flow device 20 without the need to externally control reaction time, test sample volume, etc.
[0076] Indicator zone 31 and control zone 32 generally can provide any number of distinct sensing regions so that a user can better determine the ionic strength of urine. Each region can contain the same materials or different materials. For example, zones can include two or more distinct regions (eg lines, points, etc.). The regions may be arranged in the form of lines in a direction that is substantially perpendicular to the flow of the test sample through device 20. Also, in some embodiments, the regions may be arranged in the form of lines in a direction that is substantially parallel to the flow of the test sample through device 20.
[0077] In addition, portions of one or more zones of the device described herein may be covered by a coating material 28, which limits the exposure of such zone(s) to the external environment. For example, a urine sample may evaporate if left in the air or some other environment for too long a period of time. The resulting urine can be more concentrated and can lead to inaccurate results. Therefore, the present inventor has developed a technique to reduce this problem by covering the zone(s) to limit exposure to the external environment. For example, referring to Figure 1, such a liner material 28, which covers the zone(s), may define an opening 30 to allow air to pass out of the device as urine transits into the device. device, displacing the air. The opening 30 may be of a sufficient size and dimension, as would be known in the art, to allow a sufficient amount of air to pass out of the device. In certain embodiments, a tape can be used as the backing material. Lining material can also be used to hold the device together. Additionally, the coating material can prevent the reagent from leaking out of the device or coming into contact with a user.
[0078] In certain embodiments, devices made in accordance with the present invention are capable of maintaining signal strength for at least about 2 hours, more particularly for at least about 4 hours, more particularly for at least about 2 hours. 6 hours, more particularly, for at least about 8 hours.
[0079] One embodiment of a method for detecting the ionic strength of urine using device 20 of Figure 1 will now be described in more detail. Initially, a urine test sample is applied to the sample application zone 24 and transitions in the “L” direction to the buffer zone 22. In the buffer zone 22, the ions present in the urine sample induce an ion exchange with the polyelectrolyte, thereby increasing or decreasing the concentration of hydrogen ions in urine. As the mixture flows through device 20, urine and hydrogen ions flow to indicator zone 31, where the change in hydrogen ion concentration is detected by a pH indicator. Therefore, the color or intensity of the color of the indicator zone 31 can be determined, either visually or with instrumentation. If desired, the intensity of the color in the indicator zone 31 can be measured to quantitatively or semi-quantitatively determine the ionic strength of the urine and, in turn, the USG.
[0080] The present invention provides a relatively simple, compact and cost-efficient device to accurately detect the USG. The test result can be visible so that it is readily observed by the person performing the test quickly and under test conditions that lead to highly reliable and consistent test results. Section III - Absorbent Articles
[0081] According to the present invention, one or more devices described herein may also be integrated into an absorbent article. An "absorbent article" generally refers to any article capable of absorbing water or other fluids. Examples of some absorbent articles include, but are not limited to, absorbent personal care articles, such as diapers, training pants, absorbent underwear, incontinence articles, feminine hygiene products (eg, sanitary napkins), swimwear , baby wipes and so on; medical absorbent articles such as clothing, fenestration materials, linings, bed covers, bandages, absorbent pads and medical wipes; handkerchiefs for food services; articles of clothing; and so on. Suitable materials and processes for forming such articles are well known to those skilled in the art. Typically, absorbent articles include a substantially liquid-impermeable layer (e.g., outer covering), a liquid-permeable layer (e.g., body-facing liner, flare layer, etc.), and an absorbent core.
[0082] Various embodiments of an absorbent article, which may be formed in accordance with the present invention, will now be described in more detail. For purposes of illustration only, an absorbent article is shown in Figure 2 as a diaper 101. In the illustrated embodiment, the diaper 101 is shown as having an hourglass shape in an unsecured configuration. However, of course, other shapes can be used, such as a generally rectangular, T-shaped or I-shaped shape. As shown, the diaper 101 includes a chassis formed of various components, including an outer cover 117, a body facing liner 105, an absorbent core 103 and a flare layer 107. However, it should be understood that other layers may also be used in exemplary embodiments of the present invention. Likewise, one or more of the layers referred to in Figure 2 may also be eliminated in certain exemplary embodiments of the present invention.
[0083] The body-facing liner 105 is generally employed to help isolate the wearer's skin from liquids held in the absorbent core 103. For example, the liner 105 has a body-facing surface that is typically Compatible, soft-touch and non-irritating to the user's skin. Typically, liner 105 is also less hydrophilic than absorbent core 103 so that its surface remains relatively dry to the wearer. As noted above, liner 105 may be liquid permeable to allow liquid to readily penetrate through its thickness. Exemplary liner constructions, which contain a non-woven web, are described in U.S. Patent No. 5,192,606 to Proxmire, et al.; in U.S. Patent No. 5,702,377 to Collier, IV, et al.; in U.S. Patent No. 5,931,823 to Stokes, et al.; in U.S. Patent No. 6,060,638 to Paul, et al.; and in U.S. Patent No. 6,150,002 to Varona, as well as in U.S. Patent Application Nos. 2004/0102750 from Jameson; 2005/0054255 by Morman, et al.; and 2005/0059941 to Baldwin, et al., all of which are incorporated herein in their entirety by reference thereto for all purposes.
The diaper 101 may also include a surge layer 107, which helps to decelerate and diffuse discharges or spurts of liquid that can be quickly introduced into the absorbent core 103. Desirably, the surge layer 107 quickly accepts and temporarily retains the liquid before releasing it in the storage or retaining portions of the absorbent core 103. In the illustrated embodiment, for example, the surge layer 107 is interposed between an inwardly facing surface 116 of the body-facing liner 105. and the absorbent core 103. Alternatively, the surge layer 107 may be located on an outwardly facing surface 118 of the body-facing liner 105. The surge layer 107 is typically constructed from highly permeable materials. to liquids. Examples of suitable surge layers are described in U.S. Patent No. 5,486,166 to Ellis, et al. and U.S. Patent No. 5,490,846 to Ellis, et al., which are incorporated herein in their entirety by reference thereto for all purposes.
[0085] The outer cover 117 typically is formed from a material that is substantially impermeable to liquids. For example, the outer cover 117 may be formed from a thin plastic film or other flexible liquid impervious material. In one embodiment, the outer covering 117 is formed from a polyethylene film having a thickness of from about 0.01 millimeter to about 0.05 millimeters. The film can be impermeable to liquids, but permeable to gases and water vapor (ie, “breathable”). This allows vapors to escape from the absorbent core 103, but still prevents liquid exudates from passing through the outer cover 117. If a more fabric-like feel is desired, the outer cover 117 can be formed from a polyethylene film laminated to a non-woven weft. For example, a stretch thinned polypropylene film can be thermally laminated to form a spunbond web of polypropylene fibers.
[0086] In addition to the components mentioned above, the diaper 101 may also contain various other components as is known in the art. For example, the diaper 101 may also contain a substantially hydrophilic tissue paper wrap sheet (not shown), which helps maintain the integrity of the fibrous structure of the absorbent core 103. The tissue paper wrap sheet typically is placed in around the absorbent core 103, over at least its two main facing surfaces, and composed of an absorbent cellulosic material, such as creped filler or a high moisture resistant tissue paper. The tissue paper wrap sheet can be configured to provide a capillary action layer, which helps to rapidly distribute liquid over the absorbent fiber mass of the absorbent core 103. The wrap sheet material, on one side of the absorbent fibrous mass, may be attached to the wrapping sheet located on the opposite side of the fibrous mass to effectively trap the absorbent core 103. In addition, the diaper 101 may also include a venting layer (not shown) which is positioned between the absorbent core. 103 and the outer cover 117. When used, the vent layer can help insulate the outer cover 117 from the absorbent core 103, thereby reducing moisture in the outer cover 117. Examples of such vent layers may include a non-woven web laminated to a breathable film as described in US Patent No. 6,663,611 to Blaney, et al., which is incorporated herein in its entirety by reference thereto. for all purposes.
[0087] In some embodiments, the diaper 101 may also include a pair of side panels (or ears) (not shown) that extend from the side edges 132 of the diaper 101 to one of the waist regions. The side panels can be formed integrally with a selected diaper component. For example, the side panels can be formed integrally with the outer covering 117 or from the material employed to provide the top surface. In alternative configurations, the side panels can be provided by members connected and mounted to the outer cover 117, the top surface, between the outer cover 117 and the top surface, or in various other configurations. If desired, the side panels can be stretched or otherwise made elastomeric by using the elastic non-woven composite of the present invention. Examples of absorbent articles, which include elasticized side panels and selectively shaped securing tabs, are described in PCT Patent Application WO 95/16425 to Roessler; in U.S. Patent No. 5,399,219 to Roessler, et al.; in U.S. Patent No. 5,540,796 to Fries; and U.S. Patent No. 5,595,618 to Fries, each of which is incorporated herein in its entirety by reference thereto for all purposes.
[0088] As illustrated representatively in Figure 2, the diaper 101 may also include a pair of containment flaps 112, which are configured to provide a barrier and to contain lateral flow of body exudates. The containment tabs 112 may be located along the laterally opposite side edges 132 of the body-facing liner 105, adjacent to the side edges of the absorbent core 103. The containment tabs 112 may extend longitudinally along the entire length of the core. absorbent 103, or may only partially extend along the length of the absorbent core 103. When the containment tabs 112 are shorter in length than the absorbent core 103, they may be selectively positioned anywhere along the edges. sides 132 of the diaper 101, in a crotch region 110. In one embodiment, the containment tabs 112 extend the entire length of the absorbent core 103 to better contain body exudates. Such containment tabs 112 are generally well known to those skilled in the art. For example, suitable constructions and arrangements for containment tabs 112 are described in U.S. Patent No. 4,704,116 to Enloe, which is incorporated herein in its entirety by reference thereto for all purposes.
[0089] To provide improved fit and to help reduce leakage of body exudates, the diaper 101 may be elasticized with suitable elastic members, as further explained below. For example, as illustrated representatively in Figure 2, the diaper 101 may include leg elastics 106 constructed to operatively tension the side edges of the diaper 101 to provide elasticized leg bands that can fit closely around the user legs to reduce leakage and provide improved comfort and appearance. Waistbands 108 can also be employed to stretch the end margins of the diaper 101 to provide stretchy waistbands. Waist elastics 108 are configured to provide a comfortably intimate, resilient fit around the wearer's waist.
[0090] The diaper 101 may also include one or more fasteners 130. For example, two flexible fasteners 130 are illustrated in Figure 2 at opposite side edges of waist regions to create a waist opening and a pair of leg openings. around the user. The shape of the fasteners 130 can generally vary, but can include, for example, generally rectangular shapes, square shapes, circular shapes, triangular shapes, oval shapes, linear shapes, and so on. Fasteners may include, for example, a hook and loop material, buttons, pins, snap buttons, tape fasteners, cohesives, fabric and loop fasteners, etc. In a particular embodiment, each fastener 130 includes a separate piece of hook material affixed to the inside surface of a flexible liner.
[0091] The various regions and/or components of the diaper 101 can be assembled together using any known fastening mechanism, such as adhesive, ultrasonic, thermal, etc. bonds. Suitable adhesives may include, for example, hot melt adhesives, pressure sensitive adhesives, and so on. When used, the adhesive can be applied as a uniform layer, a patterned layer, a spray-applied pattern, or any of separate lines, spirals or dots. In the illustrated embodiment, for example, the outer cover 117 and the body facing liner 105 are assembled relative to each other and relative to the absorbent core 103 using an adhesive. Alternatively, the absorbent core 103 can be connected to the outer cover 117 using conventional fasteners, such as buttons, hook-and-loop fasteners, adhesive tape fasteners, and so on. Similarly, other diaper components, such as elastic leg members 106, elastic waist members 108 and fasteners 130, can also be assembled to form the diaper 101 using any fastening mechanism.
[0092] In general, the devices of the present invention may be incorporated into the absorbent article in a variety of different orientations and configurations, as far as the device is capable of receiving urine and providing a signal to a USG user or caregiver. For example, the sampling zone and the control zone can be visible by the user or the caregiver so that a simple, accurate and quick USG indication can be provided. The visibility of such layer(s) can be realized in a variety of ways. For example, in some embodiments, the absorbent article may include a transparent or translucent portion 140 (e.g., window, film, etc.) that allows the sampling zone and/or control zone to be readily viewed without removing the user absorbent article and/or without disassembly of the absorbent article. In other embodiments, the sampling zone and/or the control zone may extend through a hole or opening in the absorbent article for observation. In still other embodiments, the sampling zone and/or the control zone may simply be positioned on a surface of the absorbent article for observation.
[0093] Regardless of the particular way in which it is integrated, urine can be discharged directly into a portion of the sampling zone, a liquid-permeable cover or other material surrounding the test device 120, or it can be discharged over a component of the absorbent article into which the testing device 120 has been integrated.
[0094] After a sufficient reaction time, the color intensity can be measured to quantitatively or semi-quantitatively determine the USG. However, although quantitative testing can be performed, qualitative testing is typically employed to provide early testing and monitoring of a health condition. Therefore, when a certain USG is detected, the user or caregiver is given an indication that additional quantitative testing can be performed. For example, a diaper having an integrated testing device can be used periodically with children or non-ambulatory patients as part of a monitoring program that tests USG. When a sufficiently high USG is indicated, additional quantitative testing can then be submitted to determine the scope and stage of the problem detected, so as to provide additional treatment information. Section IV - Empirical Examples
[0095] The following empirical examples further illustrate the present invention in detail. Example 1.
[0096] A cellulose pad was soaked with 20 mg/ml of poly(acrylic acid) (PAA) at a pH of 7.95 and air dried. The pad was then soaked with a 2.4% Oasisà (surfactant) solution in 90% ethanol and 10% water and air dried. The pad was then cut into small pieces (2 cm x 4 cm) and to each piece a small drop of 5 mg/ml Bromothymol Blue in water was applied and allowed to dry. A drop of synthetic urine of different densities was applied to a piece of dipping stick to display green, yellowish green, greenish yellow, yellow, yellow and yellow for sample densities of 1.002; 1.008; 1.014; 1.020; 1.025 and 1.035; respectively. Example 2.
[0097] A cellulose pad, deposited with 20 mg/mL of PAA at pH 8.2, was exhausted with a solution containing 2 mL of 200 mg/mL of Oasis (surfactant) and 1 mL of 5 mg/mL of Blue of Bromothymol (BTB) and air dried. The pad was cut into a 5mm wide device to display an initial blue color. The devices were sealed with Scotch tape, except for a sample application site. A sample of synthetic urine, with densities of 1.002; 1.008; 1.014; 1.020; 1.025 and 1.035 was applied to each device to display green, green, yellowish green, greenish yellow, yellow and yellow, respectively, as depicted in Figure 3. Example 3.
[0098] A cellulose pad 30 cm long and 4 cm wide, deposited with 20 mg/mL of PAA at pH 8.2, was soaked with 10 mL of 4.8% Oasis solution (surfactant) , 0.1% Tween 20 in water and ethanol (water/ethanol = 2/8) and air dried. The pad was then depleted with 5 mg/ml BTB in water/ethanol (7/3) through a Kinematic dispenser to make a narrow strip for the detection zone. The pad was then cut into 5mm wide devices. The devices were sealed by Scotch tape, except for one sample application site. A sample of synthetic urine, with densities of 1.002; 1.008; 1.014; 1.020; 1.025 and 1.035 was applied to each device to display blue, green, greenish yellow, yellow, yellow and yellow, respectively.
[0099] The present invention has been described, both generically and in detail, through examples and figures. Those skilled in the art, however, may appreciate that the invention is not necessarily limited to the specifically described embodiments, but that substitutions, modifications and variations can be made in relation to the present invention and its applications, without departing from the spirit and scope of the invention. Therefore, changes are to be construed as included herein, unless the modifications otherwise depart from the scope of the present invention as defined in the claims.

权利要求:
Claims (16)
[0001]
1. Testing device to quantitatively and semi-quantitatively determine urine density, characterized in that it comprises: a first substrate with a porous matrix adapted to conduct lateral flow, the substrate having: a contact zone with the sample and a detection zone as parts of a buffer pad; a feedback zone as part of a capillary action pad located downstream of said sensing zone; and said detection zone having a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa<10-3, and charged polymeric surfactants that respond to relative ion concentrations in a sample solution, and a pH indicator charged with a charge opposite to that of the charged polymeric surfactant.
[0002]
2. Testing device according to claim 1, characterized in that the loaded polymeric surfactant is soluble in amounts greater than or equal to 1% by weight (>1% by weight of solute) in water and in low-water aqueous solutions ionic concentration of <0.1% by weight of salts, but insoluble (<1% by weight of solute) in aqueous solution of high phonic concentrations of > 0.1% by weight of salts.
[0003]
3. Testing device according to claim 1, characterized in that said charged polymeric surfactant is present in an amount of up to 20% by weight.
[0004]
4. Testing device according to claim 1, characterized by the fact that said charged polymeric surfactant both immobilizes, in a non-diffusive manner, charged indicators, and simultaneously enhances the wettability of said first substrate.
[0005]
5. Testing device according to claim 1, characterized in that said detection zone has a pH indicator that exhibits a color transition at a pH of 5.5 to 10.5, preferably in which said device has a capillary action zone, which changes color upon contact with urine, regardless of urine density, and which has a pH indicator, immobilized in a non-diffusive way, and a pH adjuster, said pH indicator exhibits a transition of color at a pH less than 5.5 or greater than 10.5.
[0006]
6. Testing device according to claim 1, characterized in that said detection zone is largely coincident with said buffer pad.
[0007]
7. Testing device according to claim 1, characterized in that the device additionally includes a flow control zone located downstream of the detection zone, and between the detection zone and the feedback zone, spatially separating the detection and feedback zones, such that each of the preceding zones is in fluid communication with the other zone, either directly or indirectly, by an adjacent component.
[0008]
8. Testing device according to claim 1, characterized in that said weak polymeric acids or bases include poly(acrylic acid), poly(maleic acid), poly(vinyl-amine) and poly(4-vinyl- pyridine).
[0009]
9. Absorbent article capable of determining the ionic strength of urine, characterized in that it comprises: a layer substantially impervious to liquids; a liquid permeable layer; an absorbent core positioned between the substantially liquid-impervious layer and the liquid-permeable layer and a side-flow testing device integrated with the article and positioned such that the device is in fluid communication with urine when supplied by a user of the article, the device comprising: a buffering zone, the buffering zone including a polyelectrolyte disposed therein; a detection or indicator zone, the detection zone having a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa<10-3, and charged polymeric surfactants that respond to relative ion concentrations in a solution of sample, and a pH indicator charged with a charge opposite to that of the charged polymeric surfactant, non-diffusively immobilized thereon; said charged polymeric surfactant is soluble in amounts greater than or equal to 1% by weight (>1% by weight of solute), in water and in aqueous solutions of low ionic concentration of <0.1% by weight of salts, but insoluble ( < 1% by weight of solute) in aqueous solution of high phonic concentrations of > 0.1% by weight of salts.
[0010]
10. Absorbent article, according to claim 9, characterized in that said detection zone is largely coincident with the buffer zone; or wherein the detection zone is separate from the tamponade zone and positioned adjacent to and in fluid communication with the tamponade zone; with a coating material, the coating material covering at least a portion of the buffering zone and a portion of the sensing zone, to avoid exposing such covered portions to the external environment, preferably wherein the coating material defines an opening, the opening being configured to allow air to pass through it as urine passes through the device.
[0011]
11. Absorbent article according to claim 9, characterized in that the polyelectrolyte comprises poly(acrylic acid), poly(maleic acid), maleic acid-vinyl methyl ether copolymer, poly(methacrylic acid), acid copolymer styrene-maleic, maleic anhydride-methyl vinyl ether copolymer, poly(vinyl-amine), poly(4-vinyl-pyridine), partially neutralized, or combinations thereof.
[0012]
12. Absorbent article, according to claim 9, characterized in that the polyelectrolyte is immobilized in a non-diffusive way in the buffer zone.
[0013]
13. Absorbent article, according to claim 9, characterized in that the absorbent article defines a window, through which the detection zone is observable.
[0014]
14. Method to quantitatively or semi-quantitatively determine urine density, characterized by comprising: providing a fluidic device presenting a first substrate with a porous matrix adapted to conduct lateral flow, the substrate having: a contact zone with the sample and a detection zone as parts of a buffer pad; a feedback zone as part of a capillary action pad located downstream of the sensing zone; and said detection zone having a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa<10-3, and charged polymeric surfactants that respond to relative ion concentrations in a sample solution, and a pH indicator charged with a charge opposite to that of the charged polymeric surfactant; the charged polymeric surfactant is soluble in amounts greater than or equal to 1% by weight (>1% by weight of solute) in water and in aqueous solutions of low ionic concentration of <0.1% by weight of salts, but insoluble (<< 1% by weight of solute) in aqueous solution of high ionic concentrations of > 0.1% by weight of salts; the deposition of a urine sample on the contact zone with the sample; and allowing the urine sample to migrate through the buffer pad to the capillary action pad.
[0015]
15. Method of monitoring the relative density of urine, characterized in that it comprises: providing a backflow tape with a porous matrix in fluid communication with a buffer pad, a capillary action pad and a flow control zone located between the pad of buffer and capillary action pad, the buffer pad having a detection zone with a buffering component comprising a weak polymeric acid and a weak polymeric base with a pKa<10-3, and charged polymeric surfactants that respond to concentrations of relative ions in a sample solution, and a charged pH indicator with a charge opposite to that of the charged polymeric surfactant; introduce a test sample into a sample zone on the buffer pad; allowing the sample to penetrate through a detection zone to the flow control zone before developing a visual signal in an observation-feedback zone; control flow through manipulation of porosity, density or ionic affinity gradient, in a matrix fostering at least part of the flow control zone.
[0016]
16. Method according to claim 15, characterized in that the charged polymeric surfactant is soluble in amounts greater than or equal to 1% by weight, > 1% by weight of solute, in water and in low concentration aqueous solutions ionic of <0.1% by weight of salts, but insoluble, <1% by weight of solute, in aqueous solution of high phonic concentrations of >0.1% by weight of salts.

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同族专利:

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公开号 | 公开日

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US20120042722A1|2012-02-23|

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MX2013001628A|2013-03-22|

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EP2606350A4|2014-03-05|

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EP2606350A2|2013-06-26|

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WO2012023071A2|2012-02-23|

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WO2012023071A3|2012-06-07|

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EP2606350B1|2015-03-25|

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KR101444670B1|2014-09-26|

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AU2011290498B2|2014-07-03|

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BR112013003561A2|2016-06-07|

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RU2013109175A|2014-09-27|

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CN103097890A|2013-05-08|

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AR082467A1|2012-12-12|

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AU2011290498A1|2013-02-07|

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US8623292B2|2014-01-07|

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CN110478131B|2019-08-05|2022-01-11|思必康（厦门）新材料有限公司|Gauze with pH response color change, preparation method thereof and application of gauze|

法律状态:
2019-07-16| B06T| Formal requirements before examination [chapter 6.20 patent gazette]|

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2020-07-28| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|

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2021-02-09| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-04-20| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 25/07/2011, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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US12/858,204|2010-08-17|

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US12/858,204|US8623292B2|2010-08-17|2010-08-17|Dehydration sensors with ion-responsive and charged polymeric surfactants|

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PCT/IB2011/053313|WO2012023071A2|2010-08-17|2011-07-25|Dehydration sensors with ion-responsive and charged polymeric surfactants|

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