This invention relates to a soft, battery-free, flexible, non-invasive, reusable hydration sensor adherable to even small-areas and curvilinear surfaces of a body. The hydration sensor measures volumetric water content in skin as a function of depth, and wirelessly transmits data to a portable smart device. The hydration sensor includes a top layer for thermal, chemical and mechanical isolation of the hydration sensor from an environment; a bottom layer operably placed on a target area of interest on the skin; and a flexible printed circuit board (f-PCB) disposed between the top layer and the bottom layer. The f-PCB contains electronics for sensing and wireless communication. The bottom layer operably serves as a direct interface between the f-PCB and the skin and comprises a flexible adhesive for attaching the hydration sensor to the skin.

Some implementations of the disclosure relate to a wearable biosensor device including an iontophoresis module configured to stimulate production of a sweat sample from skin of a user, the sweat sample including biomarkers; a microfluidic module configured to collect the sweat sample, mix the sweat sample with labeled detection reagents to obtain a mixture including the biomarkers bound to the labeled detection reagents, and route the mixture to a detection reservoir of the microfluidic module; and a sensor assembly including a bioaffinity sensor configured to quantify the biomarkers of the mixture in the detection reservoir to determine a concentration of the biomarkers present in the sweat sample. The bioaffinity sensor includes an electrode functionalized to bind to the biomarkers of the mixture. The bioaffinity sensor can quantify the biomarkers to determine their concentration with a sensitivity on the order nanomoles or picomoles.

The present disclosure provides a method of using a wearable biofluid sensing device to develop a cytokine profile for an individual. The method includes taking concentration, ratio, and trend measurements of one or more cytokines in the individual's sweat, along with other contemporaneous device measurements to inform sweat rate, skin temperature, sweat sample pH, or other factors. The method further considers these measured values in the context of external information about the individual, and uses such information to develop (1) a baseline cytokine profile characterizing the individual's healthy cytokine levels, or (2) an inflammation profile for a physiological condition, which characterizes the expected cytokine levels for a physiological condition. Also included is a method to use a biofluid sensing device to determine whether an individual has a physiological condition by comparing device measurements to the baseline profile and inflammation profile. Results are then communicated to a device user.

A device (100) for sensing a first analyte in sweat on skin includes an analyte-specific sensor (120) for sensing the first analyte and an active sweat coupling component (130) for transporting at least one sweat sample inside the device (100) and into fluid communication with the analyte-specific sensor (120). A method of sensing a first analyte in sweat on skin includes actively transporting at least one sweat sample into fluid communication with an analyte-specific sensor (120) for sensing the first analyte using an active sweat coupling component (130) and sensing the first analyte using the analyte-specific sensor (120).

An apparatus for estimating blood concentration of an analyte may include a sweat collector configured to collect sweat from a skin surface of a user. The apparatus may include an optical sensor configured to emit light rays of different wavelengths towards the collected sweat, and detect an optical signal reflected by the collected sweat. The apparatus may include a processor configured to estimate the blood concentration of the analyte based on the detected optical signal.

A sweat sensing device (20) comprises at least one sweat generation unit (22) capable of initiating sudomotor axon reflex (SAR) sweating in an indirect stimulation region and at least one analysis unit (24, 26) capable of sensing a physiological parameter of sweat, collecting a sweat sample, or a combination thereof. The at least one analysis unit (24, 26) is located above the indirect stimulation region when the sweat sensing device is placed on skin.

Methods for treating fluid overload in a subject comprise shifting fluids directly and non-invasively from an interstitial compartment of the subject to skin of the subject through controlled local sweating. Methods of the invention allow for removal of excess fluid from the interstitial compartment of the subject and treat fluid overload in the subject. Sweat stimulation systems comprise a chamber and first and second relative humidity sensors. The chamber is sized to fit around a body part of a subject, comprises an inlet and an outlet, and is configured such that air flows through the chamber from the inlet to the outlet. The first relative humidity sensor is operably located inside the inlet, and the second relative humidity sensor is operably located proximate the outlet.

The disclosed invention provides a fluid sensing device and method capable of collecting a fluid sample, concentrating the sample with respect to one or more target analytes, and measuring the target analyte(s) in the concentrated sample. The invention is also capable of determining the change in molarity of the fluid sample with respect to the target analyte(s), as the sample is concentrated by the device. The invention further includes a method for using a fluid sensing device to concentrate a fluid sample with respect to one or more target analytes. The disclosed method further includes the ability to correlate the measured target analyte concentration to a physiological condition of a device wearer, or of a fluid source.

Methods for treating fluid overload in a subject comprise shifting fluids directly and non-invasively from an interstitial compartment of the subject to skin of the subject through controlled local sweating. Methods of the invention allow for removal of excess fluid from the interstitial compartment of the subject and treat fluid overload in the subject. Sweat stimulation systems comprise a chamber and first and second relative humidity sensors. The chamber is sized to fit around a body part of a subject, comprises an inlet and an outlet, and is configured such that air flows through the chamber from the inlet to the outlet. The first relative humidity sensor is operably located inside the inlet, and the second relative humidity sensor is operably located proximate the outlet.

Personal diagnostic devices including diagnostic patches (bio-patches) and interactive medical bracelets (bio-bracelets) are provided with a skin/patch interface, at least one analysis layer, a signal processing layer, and a user output interface. Embodiments of the interactive diagnostic devices may include micro-fluidic circuits with reaction chambers, analysis chambers, mixing cambers, and various pre-disposed chemistries or reagents for performing a wide verity of tests by trans-dermal transport of blood or perspiration. Sample collection chambers for the fluidic circuit may include minimally invasive tubules that penetrate the skin surface to acquire blood samples from capillaries near the epidermis. Alternate implementations of the personal diagnostic device may be equipped with logic processing, input/output devices, acoustic microphones, cryogenic circuits, embedded processors, electrical control circuitry, and battery current sources or photovoltaic sources of electrical power.