UC Irvine

The future of mobile health will be led by a new generation of non-invasive bodily sensors (and their encompassing networks) that will be defined by their ability to extract critical information from the body, as well as their cheap and disposable/reusable nature. While there are many promising sensor technologies, the majority of these lack the complete package of features required for many emerging applications in wearable and implantable sensing---this includes a combination of passivity (ideally microelectronics-free), wireless readout, long-term operation, and specificity. Here, we present a novel sensimetric platform that encompasses all these characteristics--- namely programmable/adaptable interlayer-RF sensors for selective chemo-mechanical measurement. Critical sensor characteristics (such as their selectivity, sensitivity, and mechanical properties) can be programmably-encoded by the structural fusion of modern electromagnetic architectures with emerging "smart" materials including engineered hydrogels, biopolymers, and nanomaterials. We devised an inexpensive and simple method for manufacturing such sensors, which are typically composed of unanchored, broad-side coupled resonators that are interceded by such novel materials. We first utilized engineered hydrogel to synthesize pressure, pH, temperature, salinity, alcohol, and glucose sensors that can be arrayed or worn on/under the skin in wearable and implantable settings. Next we utilized engineered biopolymer to manipulate the sensimetric properties of silk biopolymer-interlayer biosensors--- this enabled sensors with programmable sensitivity and selectivity to salts, sugars, and oils/fats. We achieve what we believe to be a first demonstration with these sensors, namely the co-measurement of salts, sugars, and fat directly from complex foods such as milk, meats, teas, or soups.These novel sensors are further built into unique devices and systems to facilitate their readout. Near-field communication (NFC) sensor circuits are built through the simple attachment of an LED, where direct quantification of sensor state is measured by either the cellphone or eye with no specialized electronics required at the sensing node. We propose a novel spectrometric approach for co-measuring multiple sensors' state by creating unique multi-layer networks composed entirely of passive wireless RF elements. These networks enable novel devices such as a fashionable stretchable wristbands for biometric measurement, or a SmartCup for co-monitoring the sugar, salt, fat, and temperature of drinks. Lastly, a Qi-based, near-field power transfer scheme is developed using off-the shelf sensors that can power networks to monitor the eating habits in healthy subjects, dysphagia in stroke patients, or Neonatal Abstinence Syndrome in infants.