Abstract: A power transfer-based flexible sensing platform that can be used in a fluid environment includes at least one metallic thin film structure, with a polymeric encapsulation that protects the metallic thin film structure from the fluid environment, a smart hydrogel sandwiched between layers of the metallic thin film structure, the smart hydrogel being configured to swell or shrink in response to stimulus, and an AC power source or signal generator electrically connected to the at least one metallic film structure. The metallic thin film can include first and second U-shaped metallic thin film structures, each encapsulated, where the smart hydrogel is sandwiched between them. An AC power or signal source is electrically connected to one of the U-shaped structures, causing power to be inductively transferred to the other. Measurement of the induced power or other signal can be used to determine a concentration of an analyte in the fluid environment.

Abstract: Microresonator structures including a top polymer film layer, a bottom polymer film layer, and a smart hydrogel structure sandwiched between the polymer film layers. An ultrasound resonator cavity having a resonance frequency is defined between the top and bottom polymer layers, and the smart hydrogel structure is configured to provide a change in height to the ultrasound resonator cavity due to volumetric expansion or contraction of the smart hydrogel structure, in response to interaction of the smart hydrogel structure with one or more predefined analytes in an in vivo or other environment. Related methods of use for determining the presence or concentration of a given target analyte, as well as methods of fabricating such microresonator structures are also described.

Abstract: Systems and methods for measuring changes in smart hydrogel microresonator structures positioned in an in vivo or other environment, having an acoustic resonance frequency in an ultrasound range. The system includes a smart hydrogel microresonator structure positioned within the environment configured to exhibit a change in resonance frequency in response to interaction with one or more predefined analytes in the environment. The system includes an ultrasound transducer for querying the smart hydrogel microresonator structure at or near its resonance frequency. The system also includes a computer system configured to receive ultrasound data as provided by query of the smart hydrogel microresonator structure and to determine changes in resonance frequency, amplitude or intensity of the ultrasound query wave, or mean grayscale value (MGV) associated with the ultrasound data of the smart hydrogel microresonator structure due to the change in resonance frequency.

Abstract: A biosensor (10) has a pH-sensitive polymeric hydrogel (30) in a rigid and preferably biocompatible enclosure (20). The hydrogel (30) includes an immobilized oxidoreductase enzyme such as glucose oxidase. The oxidoreductase enzyme catalyzes a chemical reaction consuming an organic molecule and producing a byproduct. The hydrogel (30) changes its osmotic pressure in proportion to the concentration of a byproduct. By measuring the change in osmotic pressure with a pressure transducer (40), the biosensor (10) is able to accurately measure the concentration of the organic molecule without the problem of interference encountered by prior art biosensors. A battery (64) powered telemeter (60) operably engaged to the pressure transducer (40) sends a radio data signal to a receiver (66) operably attached to a computer (62).