A sweat sensing device includes a plurality of sweat collection pads communicating with a sensor. Each of the pads is activated by a timing circuit which allows one or more of the pads to be activated at a selected time and subsequent deactivated after a defined period of time. This allows for selective collection of sweat from a plurality of pads over a prolonged period of time. An impedance measuring circuit can be employed to determine if one or more of the pads becomes disconnected, in order to avoid irritation. Further, the devices can use a common microfluidic device which both transports sweat activating substance, such as pilocarpine, to the surface of the skin and directs sweat away from the skin to a sensing device.

A wearable sensor decal may include a flexible wrapper layer, an intermediate layer, and a porous film layer. A first plurality of electrodes may be deposited on the wrapper layer. A heating element may be conductivity coupled to the first plurality of electrodes. A second plurality of electrodes may be deposited on the intermediate layer. A biosensor may be conductively coupled to the second plurality of electrodes. The flexible film may be hydrophilic to allow biofluids pass to the biosensor and the wrapper layer may be hydrophobic to provide waterproofing to the biosensor and heating element. The heating element may be powered to reduce thermal variance in biosensor measurements.

The described embodiments relate to a self-regulating patch for taking biopotential measurements and balancing accurate measurements and user comfort. The self-regulating patch including: a heating element operable to generate heat that causes formation of sweat at the skin surface; a biopotential sensor; an exterior surface constructed of a moisture wicking material enveloping the heating element; and a logic to concurrently activate the biopotential sensor and transition the self-regulating patch between a plurality of modes, including a comfort mode and an accuracy mode, where in the comfort mode the heating element is inactive and in the accuracy mode the heating element is active.

A blood glucose measurement device and a blood glucose measurement system using the same are proposed, the device being non-invasive, measuring blood glucose with sweat rather than blood, having a sweat-inducing means that requires no drug in a sweat induction process, and including: a sweat-inducing part having two electrodes arranged to be spaced apart from each other and to which opposite polarities are respectively applied; a housing for fixing the sweat-inducing part allowing the two electrodes to be exposed on one surface of the housing; and a blood glucose sensor inserted into the housing and in contact with body fluids induced by the sweat-inducing part, whereby pain, infection, and scars do not occur, the drugs that may affect the normal sweat-inducing mechanism in the skin are not used, and all the collected sweat is used to measure the blood glucose level with high-accuracy.

A wearable device can include a sweat collection unit, and optionally, a sweat stimulation unit. The sweat collection unit includes at least one microfluidics channel to collect sweat from a user, a chamber to hold the sweat, and a loading chamber with sweat collection paper that attracts the sweat through the chamber. A chloride sensing unit located within the chamber includes a gold working electrode and a counter electrode that can determine if enough sweat is in the chamber and, if enough, the chloride concentration of the sweat can be determined based on electrochemical reactions in response to electrical signals applied through the electrodes. A controller of the device can notify a user to trigger the sweat stimulation unit if not enough sweat is in the chamber.

A wearable device for biofluid analysis includes a set of sensing electrodes, and the set of sensing electrodes includes a working electrode which includes: (1) abase electrode including a sensing surface; (2) capture probes immobilized on the sensing surface; and (3) a protective layer e disposed on the sensing surface and including a redox couple within the protective layer.

A disposable sensor for biofluid analysis includes: (1) a conductive film having a first major surface and a second major surface opposite to the first major surface; (2) a sensing layer disposed on the first major surface of the conductive film; and (3) an adhesive layer disposed on the second major surface of the conductive film.

A non-invasive epidermal electrochemical sensor device includes an adhesive membrane; a flexible or stretchable substrate disposed over the adhesive membrane; and an anodic electrode assembly disposed over the flexible or stretchable substrate including an iontophoretic electrode. The device includes a cathodic electrode assembly disposed adjacent to the anodic electrode assembly over the flexible or stretchable substrate and includes an iontophoretic electrode. Either the cathodic electrode assembly or the anodic electrode assembly also includes a sensing electrode that includes a working electrode and at least one of a counter electrode or a reference electrode. The iontophoretic electrode in either the anodic electrode assembly or the cathodic electrode assembly that includes the sensing electrode is disposed on the substrate to at least partially encompass the working electrode and the at least one of the counter electrode or the reference electrode. The device includes an electrode interface assembly including independent electrically conductive contacts.

A sweat sensor device (200) includes one or more sweat sensors (220) and a seal (280) covering the one or more sweat sensors (220). The seal (280) is adapted to protect the sweat sensors (220) from outside contaminants when the device (200) is placed on the skin (12). The sweat sensor device (200) may include an absorbing medium (230) to absorb sweat from the skin (12) that is covered by the seal (280). The seal (280) can be permeable to gas, permeable to water and impermeable to at least one aqueous solute, or selectively permeable to at least one aqueous solute. The sweat sensor device (200) may include an artificial sweat stimulation mechanism (345) for stimulating sweat when the device (200) is placed on the skin (12).

A sensing device allows detection of biological quantities in ways that are minimally invasive. Micrometer or nanometer sized needles allow sensing of bodily fluids in a minimally invasive method. The device comprises electronics and power harvesting. Antennas or coils allow communication and power harvesting from an external device, which can be attached to smartphones to allow operation of a camera and camera light for biosensing.