Patent Description:
Access to quantitative monitoring of electrolytes, micronutrients, chemical toxins, heavy metals, and metabolites for consumers, athletes, military personnel, firefighters, heart failure patients, kidney failure patients, diabetics, cystic fibrosis patients, mental health patients, preterm newborns, and others is critical to mitigate risks of dehydration, life threatening situations, and diseases, including sepsis, acidosis, anemia, hyperbilirubinemia, and dehydration.

Athletes, intensive care patients, and newborns are known to substantially benefit from sustained monitoring during daily living and sleep. For newborns, discharge from hospitals presents a daunting challenge for parents and communities that are entrusted with tracking nutrient deficits, fluid balance, and infant growth. Significant efforts to launch food programs and micronutrient fortified food aid for infants have helped address many life-threatening nutritional deficits facing fragile preterm newborns in the early weeks following delivery.

For athletes, military, and emergency personnel, monitoring the rate at which two fluids, electrolytes, and other essential body components are lost and consumed during exertion is essential for reducing the risk of injury or death due to dehydration, hyponatremia, or hypernatremia. In many cases the available tools for measuring these fluid body component losses are bulky and non-portable (e.g. scales for measuring body weight, and high performance liquid chromatography (HPLC) for measuring ionic composition). This limitation precludes the measurement of fluid losses at the most relevant times, i.e. when a person is still active.

Point-of-care wearable sensors have the potential to measure bioanalyte levels non-invasively, and could shift routine care and metabolite management from a laboratory or a hospital setting to remote field environments, or the home. Several forms of wearable, electronic, interstitial fluid and sweat analysis systems exploit electrochemical approaches for monitoring biomarker concentrations, but do not allow for collection, capture, or subsequent analysis of discrete samples of sweat at well-defined time points. Known methods rely on absorbent patches, for example, a PharmChek® sweat patch, or coiled tubes, for example, the Macroduct® sweat collection system, and serve only as passive vehicles for collecting sweat for post-hoc analysis. These conventional devices are expensive, bulky, heavy, unattractive aesthetically, and mechanically rigid. Thus, the conventional devices prevent intimate coupling with skin during physical exercise or intensive activity, exhibit poor signal quality, and physically disturb the user.

<NPL>, discloses a soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat. Background information regarding the invention can be found in <NPL>, and in <NPL>.

Thus, it would be desirable to provide an improved wearable sweat monitoring system having an improved wearable sweat sensing device that overcomes the limitations of conventional wearable sensors and that is high quality, low cost, is a component of an accessible health monitoring system that provides medical diagnostics needed to monitor athletes, patients, and newborns outside of the clinic. Access to quality medical diagnostics for these and other users could help reduce reliance on centralized care centers and provide health officials, parents, caregivers, sports teams, and coaches with better individual and demographic data for understanding treatment measures and outcomes.

This invention relates to a wearable sweat sensing device as set out in claim <NUM> below.

Optional features of the invention are set out in the dependent claims.

Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

The present invention is directed to a wearable sweat sensing device and a sweat monitoring system that may sense sweat volume, sweat composition, and biochemical information from persons, such as athletes, patients, and newborns from one or more body locations in a clinical or an at-home environment. As described in detail below, the sweat monitoring system may relay information to the subject or other interested party in real time by analyzing images of fluid or sweat channels within the sweat sensing device with a camera, such as a smartphone camera or a camera connected to an interactive console station, e.g., a weighing station for athletes or a heart monitoring station. Processors within the smartphone or the interactive console station may analyze the image data to determine an output that defines an action to be taken, such as a recommendation of a specific formulation of electrolytes and fluids to consume to help achieve electrolyte balance, modify a real or a virtual environment, e.g., to alter a temperature or level of exertion, or to alert caregivers and/or emergency personnel. The recommended actions may be communicated to the user via the smartphone or the interactive console station.

Referring now to the drawings, there is illustrated in <FIG> a first embodiment of a sweat sensing device <NUM> in accordance with this invention. The sweat sensing device <NUM> includes a substantially flexible body <NUM> having a first or upper layer <NUM>, a second layer <NUM>, a third layer <NUM>, a fourth layer <NUM>, and a fifth or lower layer <NUM>. The upper layer <NUM> has a first or outwardly facing surface <NUM>. The lower layer <NUM> has a second or skin facing surface <NUM>. An adhesive is applied to the skin-facing surface <NUM>, and the skin-facing surface <NUM> is covered by a removable adhesive liner <NUM> formed from any desired flexible and air/oxygen impermeable material.

The illustrated first layer <NUM> and the illustrated fifth layer <NUM> are formed from clear polyurethane having a thickness of about <NUM> inches. Alternatively, the first layer <NUM> and the fifth layer <NUM> may be formed from other desired soft, flexible, and clear material, such as silicone, polyethylene, polyethylene terephthalate (PET), or polyurethane. If desired, the fifth layer <NUM> may be formed from an opaque material. The first layer <NUM> and the fifth layer <NUM> may also have other desired thicknesses. For example, the first layer <NUM> may have a thickness within about <NUM> in to about <NUM> in, and the fifth layer <NUM> may have a thickness within about <NUM> in to about <NUM> in.

The illustrated third layer <NUM> is formed from clear silicone having a thickness of about <NUM> inches. Alternatively, the third layer <NUM> may be formed from other desired soft, flexible, and clear material, such as polyurethane, polyester, or PET, and may have other desired thicknesses, such as within about <NUM> in to about <NUM> in.

The illustrated second layer <NUM> and the illustrated fourth layer <NUM> are formed from clear acrylic PSA having a thickness of about <NUM> inches. The second and fourth layers <NUM> and <NUM> are adhesive layers that bond the first layer <NUM>, the third layer <NUM>, and the fifth layer <NUM> together. The material chosen for the adhesive second and fourth layers <NUM> and <NUM> may vary based on the material of the layers to which they are applied. For example, a silicon adhesive layer may be chosen to a bond silicon layers together. Alternatively, the second and fourth layers <NUM> and <NUM> may have other desired thicknesses, such as within about <NUM> in to about <NUM> in. If desired, the first layer <NUM>, the third layer <NUM>, and the fifth layer <NUM> may be directly bonded together by any conventional means, such as by ultrasonic welding.

One or more sweat channels may be formed in at least the third layer <NUM>. As shown in embodiment of the sweat sensing device <NUM> illustrated in <FIG>, a first sweat channel <NUM> is formed in the third layer <NUM> and defines a serpentine pathway. Alternately, and as shown in the illustrated embodiment of the sweat sensing device <NUM>, the first sweat channel <NUM> is also formed in the second and fourth layers <NUM> and <NUM>, respectively. The first sweat channel <NUM> has a sweat inlet end <NUM> and a sweat outlet end <NUM> at a peripheral edge of the sweat sensing device <NUM> and positioned to allow sweat to exit the first sweat channel <NUM>. The first sweat channel <NUM> may also include a biochemical assay well <NUM> near the sweat inlet end <NUM>.

Additionally, a sweat channel may be formed such that portions of the sweat channel are variously formed in the second layer <NUM>, the third layer <NUM>, and in the fourth layer <NUM>, or in combinations of layers, such as in the second and third layers <NUM> and <NUM> and in the third and fourth layers <NUM> and <NUM>. Varying a height of the sweat channel throughout its length in this manner allows areas of greater sweat channel height to be positioned in the flexible body <NUM> as a visual indicator wherein a color change within the portions of the sweat channel having the greater height may be more easily seen because a larger volume of dye therein may appear darker in color.

When a sweat channel is formed having different heights throughout its length, i.e., when portions of the sweat channel are variously formed in the layers thereof, the sweat channel may crossover itself, allowing for a longer sweat channel without the need to increase the size of the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

As best shown in <FIG>, a second sweat channel <NUM> is also formed in the second, third, and fourth layers <NUM>, <NUM>, and <NUM>, respectively. The second sweat channel <NUM> has a sweat inlet end <NUM> and a second end <NUM> that, unlike the first sweat channel <NUM>, does not define a sweat outlet. The second sweat channel <NUM> may also include a biochemical assay well <NUM> near the sweat inlet end <NUM>.

The lower layer <NUM> may have fluid or sweat inlet ports in fluid communication with the sweat channels. As best shown in <FIG>, the lower layer <NUM> includes a first sweat inlet port <NUM> in fluid communication with the first sweat channel <NUM>, and a second sweat inlet port <NUM> in fluid communication with the second sweat channel <NUM>. In the illustrated embodiment of the sweat sensing device <NUM>, the biochemical assay wells <NUM> and <NUM> extend through the lower layer <NUM> to allow for the insertion a chemical assay therein.

As shown in <FIG>, a portion 42A of the first sweat inlet port <NUM> in the lower layer <NUM> may be smaller than the portions of the first sweat inlet port <NUM> formed in the second, third, and fourth layers, <NUM>, <NUM>, and <NUM>, respectively. Similarly, a portion 40A of the biochemical assay well <NUM>, and a portion (not shown) of the biochemical assay well <NUM>, in the lower layer <NUM> may be smaller than the portions of the biochemical assay wells <NUM> and <NUM> formed in the second, third, and fourth layers, <NUM>, <NUM>, and <NUM>, respectively.

After the assay wells <NUM> and <NUM> are formed and the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are assembled, a desired biochemical or chemical assay material, described in detail below, may be disposed therein. The assay wells <NUM> and <NUM> may then be closed with an adhesive layer <NUM>, formed from any desired flexible material, such as the same material as the lower layer <NUM> to which the adhesive layer <NUM> is attached.

The sweat channels and ports may be formed in the second, third, fourth, and fifth layers <NUM>, <NUM>, <NUM>, and <NUM> by any desired means, such as with a laser, or die cut. For example, sheets or blanks of material comprising the layers of a second embodiment of a sweat sensing device <NUM> are shown in <FIG>. The assembled sweat sensing device <NUM> is also shown in <FIG>. For example, <FIG> is a plan view of a sheet or blank of material of a first or upper layer <NUM> of the sweat sensing device <NUM>. <FIG> is a plan view of a blank of material of one of an inner layer <NUM> of the sweat sensing device <NUM>, such as any one of the second, third, fourth layers <NUM>, <NUM>, and <NUM> of the sweat sensing device <NUM> described above. <FIG> is a plan view of a blank of material of a lower layer <NUM> of the sweat sensing device <NUM>. Each of the blanks <NUM>, <NUM>, and <NUM> include alignment holes <NUM> formed therein for aligning the blanks <NUM>, <NUM>, and <NUM> in a fixture, jig, or similar device (not shown).

As shown in <FIG>, the inner layer <NUM> has a first sweat channel <NUM> formed therein. The first sweat channel <NUM> has a sweat inlet end <NUM> and a second end <NUM>. The first sweat channel <NUM> may also include one or more biochemical assay wells <NUM> near the sweat inlet end <NUM>.

The lower layer <NUM> may have a sweat inlet port in fluid communication with the sweat channel. As best shown in <FIG>, the lower layer <NUM> includes a first sweat inlet port <NUM> in fluid communication with the first sweat channel <NUM>. The one or more biochemical assay wells <NUM> extend through the lower layer <NUM>.

It will be understood that a width W1 of the sweat channels, and a diameter of the assay wells, in the embodiments of the improved sweat sensing devices described herein may vary with the specific application of the sweat sensing device. The illustrated sweat channels <NUM>, <NUM>, and <NUM> may have any desired width W1, such as width of about <NUM> in. Alternatively, the sweat channels <NUM>, <NUM>, and <NUM> may have a width W1 within about <NUM> in to about <NUM> in. The inlet ports <NUM>, <NUM>, and <NUM> and the biochemical assay wells <NUM>, <NUM>, and <NUM> may have any desired diameter, such as diameter of about <NUM> in and <NUM>, respectively. Alternatively, the inlet ports <NUM>, <NUM>, and <NUM> may have a diameter of about <NUM> in to about <NUM> in, and the biochemical assay wells <NUM>, <NUM>, and <NUM> may have a diameter of about <NUM> in to about <NUM> in.

Although the illustrated inlet ports and assay wells are shown having a circular transverse section, the inlet ports and assay wells may be formed having other shapes, such as having a square transverse section, or other geometric shapes.

The biochemical assay wells <NUM> and <NUM> define colorimetric reaction sites that may be configured to react with very small, such as microliter volumes of sweat. The assay wells <NUM> and <NUM> may contain colored dyes, for example conventional food coloring dyes), chemical assays, fluoroscopic dyes, enzymatic assays, heavy metal assays, and protein/DNA based assays. In the sweat sensing device <NUM>, one assay well <NUM> is formed in the sweat channel <NUM> and one assay well <NUM> is formed in the sweat channel <NUM>. In the sweat sensing device <NUM>, two assay wells <NUM> are formed in the sweat channel <NUM> near the sweat inlet port <NUM>.

It will be understood that the sweat sensing devices disclosed herein, such as the sweat sensing devices <NUM>, <NUM>, and <NUM> (and the sweat sensing devices <NUM> and <NUM> described below), may be formed such that the depths of the sweat channels and/or the assay well vary. The color change induced by a chemical reaction will vary with a depth of the sweat channel or assay well according to the Beer-Lambert law. Measuring the color change in the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> at multiple depths may help reduce any negative effects related to lighting, exposure, and focus.

If desired, the outwardly facing surface <NUM> of the sweat sensing device <NUM> may be laminated with a very thin layer of polymer (not shown), such as a <NUM> layer of PET, having indicia printed thereon. The indicia may, for example, be aligned with the sweat channels <NUM> and/or <NUM> to highlight selected areas of the channels <NUM> and/or <NUM> for optical image capture.

The sweat sensing devices disclosed herein, such as the sweat sensing devices <NUM>, <NUM>, and <NUM> (and the sweat sensing devices <NUM> and <NUM> described below), may be used in a wearable sweat monitoring system <NUM>, described in detail below and that analyzes sweat and applies the analysis to provide feedback to the user, patient, and/or caregiver, and to modify the operation or condition of one or more environments or systems. Advantageously, one or more people may be monitored by one or more sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> that are configured to detect and indicate one or more physiologic or biometric condition of the person or persons to which they are attached. The conditions include, but are not limited to, sweat volume, sweat volume loss, sweat rate, sweat chloride loss, sweat sodium loss, sweat lactate loss, sweat electrolyte loss, sweat metabolite loss, sweat pH, sweat glucose, and foreign chemical and toxin concentrations in sweat.

Referring now to <FIG>, a diagram of the first embodiment of a wearable sweat monitoring system including the sweat sensing device <NUM>, <NUM> according to this invention is shown at <NUM>, and shows the flow of data therethrough. The wearable sweat monitoring system <NUM> is described in detail below and includes a person, such as an athlete <NUM> to whom a sweat sensing device, such as the sweat sensing device <NUM> has been affixed. The wearable sweat monitoring system <NUM> further includes an interactive console station <NUM> and/or a smartphone <NUM>, and an output message <NUM>, such as a recommendation to consume a specific formulation of electrolytes, such as a specific electrolyte replenishment beverage, carbohydrates, and fluids to consume to achieve electrolyte and metabolite balance in the user, a recommendation to consume specific nutrients, or a signal that modifies the operation or condition of one or more environments or systems.

If desired, the sweat channels, such as the sweat channels <NUM>, <NUM>, and/or <NUM> may have colored dye, such as red food coloring dye, deposited therein. In these embodiments, the sweat sensing devices <NUM>, <NUM>, and <NUM> are configured to measure sweat volume in the sweat channels <NUM>, <NUM>, and/or <NUM>, and may be further configured to measure chloride concentration in the biochemical assay wells <NUM>, <NUM>, and <NUM>. The sweat volume in the sweat channels <NUM>, <NUM>, and/or <NUM> may be displayed colorimetrically. The chloride concentration in the biochemical assay wells <NUM>, <NUM>, and <NUM> may be displayed thermochromically. For example, the indicia on the polymer laminate (not shown) applied to the outwardly facing surface <NUM> and described above may include an indicator of the chloride concentration level.

It has been shown that chloranilate will react with chloride in sweat. It has been further shown that the concentration of chlorine in the sweat present in the biochemical assay wells <NUM>, <NUM>, and <NUM> may be indicated by the shade of purple displayed therein. To assist in immobilizing the chloranilate in the biochemical assay wells <NUM>, <NUM>, and <NUM> and to prevent the chloranilate from flowing through the sweat channels <NUM>, <NUM>, and/or <NUM> during extended periods of storage, suspensions of p-HEMA or polyethylene glycol (PEG) are added to the chloranilate in the biochemical assay wells <NUM>, <NUM>, and <NUM>. The biochemical assay wells <NUM>, <NUM>, and <NUM> may contain dehydrated portions of colored dyes. The dehydrated colored dyes will then change color when mixed with sweat. If desired, other chemical assays may be used to test the sweat for other desired sweat conditions or parameters, such as blood glucose, lactic acid, and sweat volume.

In the present invention as defined in claim <NUM>, this color and/or color change in the sweat channels <NUM>, <NUM>, and/or <NUM> and in the biochemical assay wells <NUM>, <NUM>, and <NUM> is then viewed and assessed by the user, or measured and quantified by an external device, such as the camera of the smartphone <NUM>, a camera or other imaging device attached to the interactive console station <NUM>, or other means of deriving a quantified measurement from a color and/or color change. Advantageously, the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be viewed and quantified by the user, or measured and optionally quantified by the external device in real-time while the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> is on the user's body. This allows recommendations for nutrition, such as electrolyte replenishment and recommendations for environmental changes, as described in detail below, to be provided to the user while the user is still engaged in physical activity or has just completed the physical activity.

A third embodiment of the sweat sensing device is shown at <NUM> in <FIG>. The sweat sensing device <NUM> is similar to the sweat sensing device <NUM>, but additionally includes a second sweat channel <NUM> configured to measure temperature. The second sweat channel <NUM> includes a second sweat inlet port <NUM> that extends through the lower layer <NUM> and is in fluid communication with the second sweat channel <NUM>. A color viewing window <NUM> is formed at a distal end of the second sweat channel <NUM>, and a chloranilate mixing well <NUM> is formed intermediate the second sweat inlet port <NUM> and the color viewing window <NUM>. As described above, sweat may enter the second sweat channel <NUM> through the sweat inlet port <NUM> and travel to the chloranilate mixing well <NUM> where the sweat mixes with the chloranilate. The combined sweat and chloranilate my then travel within the sweat channel <NUM> to the color viewing window <NUM>, wherein the sweat-chloranilate mixed has changed color in a manner detectable to the naked eye and/or an external device, such as the camera of the smartphone <NUM>, a camera or other imaging device attached to the interactive console station <NUM>, or other means of deriving a quantified measurement from a color and/or color change.

Referring now to <FIG>, any of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> disclosed herein may include the sweat channel <NUM> configured to measure temperature (also shown in <FIG>). The sweat channel <NUM> includes the sweat inlet port <NUM> that extends through the lower layer <NUM> (see <FIG>) and is in fluid communication with the second sweat channel <NUM>. The color viewing window <NUM> is formed at a distal end of the second sweat channel <NUM>, and the chloranilate mixing well <NUM> is formed intermediate the second sweat inlet port <NUM> and the color viewing window <NUM>.

In the illustrated embodiment, the chloranilate mixing well <NUM> includes an encapsulated thermochromic ink that is tuned to measure temperature. Examples of suitable thermochromic inks include, but are not limited to, inks having cholesteric and chiral nematic structures. The ink may be deposited directly between laminating layers of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, such as between the second layer <NUM> and the fourth layer <NUM> as shown in <FIG>, or between the first layer <NUM> and the fifth layer <NUM> in embodiment without the second layer <NUM> and the fourth layer <NUM>. Alternatively, the sweat channel <NUM> may be formed in a pre-assembled, modular strip (not shown) and attached to the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

The thermochromic ink will change color as the sweat temperature is increased, for example from colorless to red, orange, yellow, green, blue, and violet. Alternatively, a thermochromic ink may be selected that is temperature insensitive and will thus change color only at a pre-determined specific transition temperature. With such a temperature insensitive ink, when the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> reaches the transition temperature, the thermochromic ink changes color.

The sweat channel <NUM> may also include an adjacent temperature indicator <NUM> that assigns a temperature value to a color as may appear in the color viewing window <NUM>. If desired, the sweat channel <NUM> may also include an adjacent elapsed time indicator <NUM>. The sweat inlet port <NUM> and the chloranilate mixing well <NUM> may be covered by a removable adhesive liner (not shown in <FIG>, but similar to the liner <NUM>), to cover sweat inlet port <NUM> and the chloranilate mixing well <NUM> and to hide the sweat, sweat-chloranilate mixture, and/or sweat-thermochromic ink mixture contained therein.

As shown in <FIG>, oxidizing ink may be placed in a plurality of wells <NUM>. When in use, the liner covering the elapsed time indicator <NUM> is removed, the wells <NUM> are exposed to air, and the inks begin to change color. The change in color of the ink may serve as an indicator of the time the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> has been on the body. As shown, the elapsed time indicator <NUM> includes the plurality of wells <NUM>, each with an ink formulation of increasingly slower reaction time, creating a graphic representation of time elapsed as shown at <NUM> in <FIG>, i.e., circles having different colors at different time intervals. The oxidizing ink may be composed of polyphenol oxidase suspended in hydrogel or in cellulose. Inhibitors such as tentoxin or tropolone may be used to lengthen the duration of time before the ink changes color.

The removable adhesive liner (not shown) may cover the elapsed time indicator <NUM> and may have an oxygen scavenger, such as the oxygen scavenger <NUM> described below, attached to an inside surface thereof. When the removable adhesive liner (not shown) is applied to a sweat sensing device, it is positioned to cover and engage the elapsed time indicator <NUM> and prevents activation thereof. When the removable adhesive liner (not shown) is removed from the elapsed time indicator <NUM>, the ink therein is exposed to oxygen and the colorimetric timer, i.e., the elapsed time indicator <NUM>, is started.

In addition to the circles having different colors at different time intervals to represent elapsed time as shown at <NUM> in <FIG>, the elapsed time indicator <NUM> may be configured as a word or words, dots, or other shapes that become visible over time. For example, the elapsed time indicator <NUM> may spell out the word "Expired" after a pre-determined period of time.

Alternatively, the elapsed time indicator <NUM> may include one or more conventional redox dye-based indicators, such as used for food packaging. One non-limiting example of such an indicator is the Ageless Eye®, produced by the Mitsubishi Gas Company.

As shown in <FIG>, the channel <NUM> may alternatively include an adjacent electronic device or sensor <NUM>. Such a sensor <NUM> may be a temperature measurement and wear timer, such as an electronic device or any of the chemical sensors described herein. Additionally, the sensor <NUM> may be any other type of sensor, such as a timer or a sensor configured to detect a desired physiological parameter, such as ECG, PPG, heart rate, and respiration rate. The device or sensor <NUM> may also be configured to for wireless communication with the interactive console station <NUM> or the smartphone <NUM> in the wearable sweat monitoring system <NUM>.

It will be understood that any of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> described herein may have one or more the channels <NUM> formed therein, each of which may include the temperature indicator <NUM>, adjacent elapsed time indicator <NUM>, and or the sensor <NUM>.

<FIG> is a cross-sectional elevational view of a sixth embodiment of the sweat sensing device <NUM>. The sweat sensing device <NUM> is similar to the sweat sensing device <NUM> and includes the upper layer <NUM>, the second layer <NUM>, the third layer <NUM>, the fourth layer <NUM>, the lower layer <NUM>, the outwardly facing surface <NUM>, and the skin-facing surface <NUM>. The sweat sensing device <NUM> also includes the sweat inlet port <NUM> in fluid communication with the sweat channel <NUM>. An adhesive is applied to the skin-facing surface <NUM>, and the skin-facing surface <NUM> is covered by the removable adhesive liner <NUM>.

The sweat sensing device <NUM> may include a conventional flexible printed circuit board (PCB) <NUM> mounted to the outwardly facing surface <NUM>. A battery, such as a zinc-air battery <NUM>, an antenna, such as a near field communication (NFC) antenna <NUM>, and a microprocessor <NUM> are operatively connected and mounted to the PCB <NUM>.

A removable adhesive liner <NUM> may be attached to the outwardly facing surface <NUM> such that it covers the PCB <NUM>. The illustrated removable adhesive liner <NUM> has the oxygen scavenger <NUM> attached to an inside surface thereof. The removable adhesive liner <NUM> may be formed from any desired material. When the removable adhesive liner <NUM> is applied to the outwardly facing surface <NUM>, the oxygen scavenger <NUM> engages the zinc-air battery <NUM> and prevents activation thereof.

The microprocessor <NUM> may be any desired microprocessor, such as an NXP NHS3100 smart sensor with an embedded temperature sensor, or a Texas Instruments RF430FRL152 sensor transponder, which includes an integrated microcontroller and an analog to digital converter and temperature sensor. Additionally, the microprocessor <NUM> may be any microprocessor configured to have additional sensors attached thereto. For example, such additional sensors may include impedance, salinity, and pressure sensors (not shown). Advantageously, the NFC enabled integrated circuit devices may power themselves from the power harvested of the modulated <NUM> current induced from an NFC-enabled smartphone <NUM> or tablet (not shown) in proximity of the sweat sensing device <NUM>. When the smartphone <NUM> or tablet (not shown) is brought into proximity of the sweat sensing device <NUM>, the sensors on the PCB <NUM> may measure the desired conditions of the sweat, e.g., temperature.

If desired, the microprocessor <NUM> may include a built-in clock/timer, and thus may record the time elapsed if the clock/timer is activated when the sweat sensing device <NUM> is applied to the skin of the user. For example, the NXP NHS3100 has a built in oscillator and memory register that may measure elapsed time beginning when the sweat sensing device <NUM> was applied and activated.

Another method of easily activating the clock/timer upon applying the sweat sensing device <NUM> to the user is with the zinc-air battery <NUM>. When the removable adhesive liner <NUM> is applied to the outwardly facing surface <NUM>, the oxygen scavenger <NUM> is positioned to engage the zinc-air battery <NUM> and prevent activation thereof.

The removable adhesive liner <NUM> must be removed before the sweat sensing device <NUM> may be applied to the skin of the user. When the user additionally removes the removable adhesive liner <NUM> from the outwardly facing surface <NUM>, the zinc-air battery <NUM> is exposed to air, is activated, and thus provides power to the microprocessor <NUM>, and any timer or sensor mounted thereon.

<FIG> is a cross-sectional elevational view of a seventh embodiment of the sweat sensing device <NUM>. The sweat sensing device <NUM> is similar to the sweat sensing device <NUM> and includes the upper layer <NUM>, the second layer <NUM>, the third layer <NUM>, the fourth layer <NUM>, the lower layer <NUM>, the outwardly facing surface <NUM>, and the skin-facing surface <NUM>. The sweat sensing device <NUM> also includes the sweat inlet port <NUM> in fluid communication with the sweat channel <NUM>. An adhesive is applied to the skin-facing surface <NUM>, and the skin-facing surface <NUM> is covered by the removable adhesive liner <NUM>. In <FIG>, the sweat sensing device <NUM> includes a chloranilate mixing well <NUM> having encapsulated thermochromic ink therein that is tuned to measure temperature, as described above. The sweat sensing device <NUM> also includes a well <NUM> covered by a removable adhesive liner <NUM> having an oxygen scavenger <NUM> attached to an inside surface thereof.

Oxidizing ink <NUM> may be placed in the well <NUM> defining a timer. When in use, the liner <NUM> is removed, the well <NUM> is exposed to air, allowing the ink <NUM> therein to begin to change color and thus starting the timer. The change in color of the ink serves as an indicator of the time the sweat sensing device <NUM> has been on the body. The oxidizing ink <NUM> may be one of the inks described herein above.

Advantageously, wearable sweat monitoring system <NUM> and the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> described herein provide an improved system and method for sweat based analysis and for applying this analysis to provide feedback to the user. This analysis and feedback may then be used to modify the operation or condition of one or more environments or systems based on one or more monitored, including but not limited to sweat volume loss, sweat rate loss, sweat electrolyte loss, sweat metabolite loss, and/or foreign chemicals/toxin concentrations in sweat.

As shown in <FIG>, the sensed and collected condition information may be relayed to the interactive console station <NUM> and/or the smartphone <NUM> used to modify the operation of the wearable sweat monitoring system <NUM> and the environment in which the user is located. Additionally, a user may use the smartphone <NUM> to collect condition information and then relay that information to the interactive console station <NUM>. The interactive console station <NUM> and the smartphone <NUM> may also be used independently of each other to collect condition information. For example, the sensed and collected condition information may cause an algorithm or computer program to be executed, e.g., started or stopped, or to change the flow of an executing program, function, or process.

A weighing station for example, may capture an image of the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, analyze sweat volume, sweat rate, and electrolyte/metabolite loss information, and relay this information to a user, a patient, and/or a caregiver about fluid electrolyte and volume replenishment to replenish the users lost wet weight. Additionally, the sweat composition sensor, e.g., a chloride/sodium electrolyte sensor of the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> may transmit a chloride concentration level to the interactive console station <NUM> and/or the smartphone <NUM>, which may then make a virtual representation, e.g., an avatar, in a virtual environment exhibit the same or exaggerated dehydration characteristics of the user, such as an athlete.

Additionally, the sensed condition information collected by the wearable sweat monitoring system <NUM> may be used to modify the system output <NUM>, for example by making a recommendation to alter a temperature, making a recommendation to alter a level of exertion, sending an alert to a caregiver or to emergency personnel, sending a signal that causes the room temperature to change to mitigate risks of dehydration or heat injury, sending a signal that activates a weighing station to measure heart rate or body temperature, and a signal that dims the lights or turns on a motorized fan in the user's environment causing the room temperature to change to mitigate further risks of dehydration or heat injury such as heat exhaustion.

Referring again to <FIG>, the interactive console <NUM> may be any conventional interactive device or environment, including but not limited to a cloud server, a sports weighing station console, a virtual reality or augmented reality controller, a smart bottle sensor, and any device configured to provide feedback to the user, a coach, a medical professional, and the like.

In addition to recommending a specific electrolyte replenishment beverage or other nutrient, the wearable sweat monitoring system <NUM> may use the data collected from the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> to alter the lighting of a wirelessly enabled training room, change the temperature in a wirelessly enabled training room, recommend a new training regimen to the user, and provide other recommendations to modify the user's sweat rate, fluid intake, or environment based on the measured values. The information collected from the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may also be used to ensure a safe operating environment by warning coaches, training staff, or medical professionals about electrolyte imbalances, injuries or possible injuries, cardiac conditions, and other potentially unsafe conditions for the user.

Advantageously, by using the wearable sweat monitoring system <NUM>, one or more people may be monitored by one or more sweat sensing devices that indicate one or more conditions of the people to which the sweat sensing device or devices are attached. The conditions monitored and indicated may include physical conditions, such as location and motion of the person or a portion of the person's body. The conditions may also include physiologic or biologic conditions, such as the mechanical, physical, thermal and/or biochemical aspects of functions and/or processes of the person. The conditions may further include detection of chemical toxins, e.g., lead, mercury, and carcinogens, and stress biomarkers, e.g. cortisol, for mental, emotional, and psychiatric conditions, such as mood, focus, concentration, depression, and alertness.

The information monitored and indicated from one or more persons may be collected and processed or analyzed, and used as a direct input or used to select or modify an input to the interactive console station <NUM>, or the smartphone <NUM> that controls the interactive environment experienced by the person. The interactive console station <NUM> and the smartphone <NUM> may use an integral or connected camera to take as input a picture and a color intensity of the sweat sensing devices10, <NUM>, <NUM>, <NUM>, and <NUM>, and then uses this information to recommend a way to balance the missing nutrients, such as through fluid and nutrient replenishment, and/or to modify the environmental conditions, such as the temperature, humidity, background music, video, and lighting conditions.

The interactive console station <NUM> and the smartphone <NUM> may use one or more algorithms to determine whether to modify the environment or the operation of a system or machine. For example, the algorithm may use one or more detected physiologic or biometric conditions, such as sweat volume, sweat volume loss, sweat rate, sweat chloride loss, sweat sodium loss, sweat lactate loss, sweat electrolyte loss, sweat metabolite loss, sweat pH, sweat glucose, and foreign chemical and toxin concentrations in the sweat, or a rate of change of these detected physiologic or biometric conditions, to then influence or modify the operation of the interactive console station <NUM> and/or the smartphone <NUM>.

The algorithm may, for example, provide information about diet, modifying intensity of training, meditation routines to control breathing, or modifications in sports hydration drink intake, including providing a personalized electrolyte recipe for the user to replenish lost nutrients. Additionally, the algorithm may compare one or more parameters representative of one or more sensed conditions to a predefined threshold value, a range of values, or a previous recorded value for an athlete and/or a team to compare past performance or population datasets.

The interactive console station <NUM> and/or the smartphone <NUM> may have image correction algorithms to correct for the effects of shadowing, glare, brightness variations, and specular reflections on the outwardly facing surfaces of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, such as the outwardly facing surface <NUM>. The sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may include indicia imprinted on the polymer layer (not shown) that may be laminated to the outwardly facing surfaces thereof. The indicia may include color calibration landmarks used to subtract the effects of disparate lighting conditions and the effects of shadows. The image processing and analysis of the outwardly facing surfaces of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> results in a measurement of sweat volume and chloride concentration, which may be relayed back to the user or may be applied as an input to change recommend a change to the surrounding environment. The indicia may also include any work or work or symbol, such as a brand name or trademark.

The sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may also contain embedded thin film electronics modules or devices for sensing, power management, and wireless communication, such as for example, the NFC antenna <NUM>, or a Bluetooth® device. These electronics devices may be packaged or bare-die electronics parts and may be embedded within the inner layers, such as the second, third, and fourth layers <NUM>, <NUM>, and <NUM>, respectively, thereby providing a moisture barrier to protect the electronics devices.

An image of part or all of the outwardly facing surface of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be used to quantify the volume of sweat collected and the rate of sweat production. Sweat volume may be determined by measuring the distance of sweat propagation along a sweat channel, such as the sweat channel <NUM>, and converting distance to volume using the known channel geometry of a given sweat sensing device. Volumetric sweat rate as a function of time, e.g., liters per hour, may optionally be determined from any of the embodiments of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> described herein, if the time at which the sweat sensing device was applied to the skin is known.

In accordance with some embodiments of the invention, a whole-body sweat volume and/or whole-body sweat rate may be quantified from the sweat sensing device. If the sweat sensing device is attached to the skin of the user and the sweat collection area is known, the sweat volume, measured as described above, may be extrapolated to a whole-body sweat volume. If desired, information about the location of the sweat sensing device on the wearer's body and/or the sweat characteristics of the wearer may be used to extrapolate the whole-body sweat volume.

As described above, the presence and concentration of various biochemical components of sweat may be measured colorimetrically on the improved sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The color and/or color change measured may be introduced or generated by a chemical reaction that is known to indicate the biochemical component of interest.

The color of the sweat in the sweat channels and the various assay wells may be measured relative to one or more reference colors on the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. These reference colors may include, but are not limited to, colors printed on the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> before, during, or after manufacture, colors generated by the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> as a result of fluid flow, and colors present in the ambient environment around the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Colorimetric measurements may also use any relevant information about the measurement system, including, but not limited to, sensor type, color sensitivity, exposure time, focal distance, and depth of focus.

Because of the relatively small size of the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> and the fluid flow channels therein, sweat measurements are performed on time-limited samples of sweat by collecting restricted volumes of sweat in isolated regions, i.e., the sweat channels, of the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The measurement area may allow measurement of electrical impedance of the sweat in the capture volume.

As noted above, the sweat channels described herein may be variously formed in the second layer <NUM>, the third layer <NUM>, and in the fourth layer <NUM>, or in combinations of layers, such as in the second and third layers <NUM> and <NUM> and in the third and fourth layers <NUM> and <NUM>. By spacing areas of increase height at pre-determined intervals in the sweat channel a fluid flow rate can be determined as the fluid in the channel travels between each area of increased channel height, and thus between areas wherein the color change within the sweat channel may be more easily seen because a larger volume of dye therein may appear darker.

The rate of flow of sweat past a measurement area, such as any pre-determined and identified region of interest on the sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> is controlled to ensure that any colorimetric, electrical, or other means of measurement reaches an equilibrium state while the sweat is still in the measurement area, i.e., that any reaction between sweat and an assay within the region is fully complete and or dye used therein is evenly diffused.

The sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> measures sweat rate and biochemical composition as a function of time. A sweat rate may be measured as a function of time by measuring sweat volume at predetermined time intervals. Biochemical composition may be measured as a function of time by measuring limited-volume sweat samples collected over a known time period.

The sweat sensing devices <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be adhered to the forearm, head, shoulders, arms, hands, torso, chest, legs and feet of the user.

The sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may detect and measure the rate of sweat loss, sweat composition, and chemical toxin and/or metabolite levels in sweat. Once the detection and measurement is completed, sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be peeled off of the skin and discarded.

Preferably, the chemicals deposited in the biochemical assay wells chemical assays are positioned therein to ensure optimal reaction conditions for the sweat as it flows through the sweat channel. Depositing chemicals within biochemical assay wells having relatively large surface areas, such as a diameter within about <NUM> in to about <NUM> in ensures optimal exposure to sweat and increases the likelihood of reaction with electrolytes in the sweat. Increasing the surface area of contact between the chemicals in the biochemical assay wells increases the chemical reaction with the sweat and thereby helps overcome the diffusion time constant limitations.

The colorimetric information on the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be analyzed by algorithms within the interactive console station <NUM> and/or the smartphone <NUM>, and a recommendation, such as the most suitable electrolyte infused drink to be consumed, may be displayed back to the user via the smartphone <NUM> or a display screen of the interactive console station <NUM>.

Additionally, the colored dyes used in the sweat sensing device <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be customized and personalized by depositing specific colored dyes in the sweat channels to match the fluid color of a specific sports drink. For example, a blue colored sports drink may be matched with a sensing device having a blue colored dye deposited in the sweat channel.

Claim 1:
A sweat sensing device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a flexible body (<NUM>) formed from five layers (<NUM>,<NUM>, <NUM>, <NUM>, <NUM>) of material bonded together and having a first, outwardly facing surface (<NUM>) and a second, skin facing surface;
a first sweat channel (<NUM>) formed in the body (<NUM>), the first sweat channel (<NUM>) having a first end defining a fluid inlet and a second end (<NUM>,<NUM>), wherein the first sweat channel (<NUM>) is formed in the three inner layers (<NUM>, <NUM>, <NUM>) of the five layers (<NUM>,<NUM>, <NUM>, <NUM>, <NUM>);
a biochemical assay well (<NUM>) formed in the first sweat channel (<NUM>); and
an assay material disposed in the biochemical assay well (<NUM>) of the first sweat channel (<NUM>), the assay material positioned to react with sweat traveling through the first sweat channel (<NUM>) and to provide one of a visual indicator of the flow of the sweat in the first sweat channel (<NUM>) and an indicator detectable by a camera and a processor connected to the camera; and
a second sweat channel (<NUM>, <NUM>) formed in the body (<NUM>), the second sweat channel (<NUM>, <NUM>) including a first end defining a fluid inlet (<NUM>) and a second end, a color viewing window (<NUM>) formed in the second sweat channel (<NUM>, <NUM>), and a biochemical assay well (<NUM>) formed in the second sweat channel (<NUM>, <NUM>) between the first end and the color viewing window (<NUM>);
wherein the biochemical assay well (<NUM>) of the second sweat channel (<NUM>, <NUM>) defines a chloranilate mixing well (<NUM>, <NUM>), the sweat sensing device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) further including chloranilate disposed in the biochemical assay well (<NUM>), and wherein the chloranilate is suspended in a suspension of one of p-HEMA and polyethylene glycol, the color viewing window (<NUM>) positioned to collect sweat that has passed through and reacted with the chloranilate in the biochemical assay well (<NUM>), and to provide one of a visual indicator and an indicator detectable by a camera and connected processor of a color of the sweat and chloranilate in the color viewing window (<NUM>).