A 3-$\mu\hbox{W}$ CMOS Glucose Sensor for Wireless Contact-Lens Tear Glucose Monitoring

Powering electronic contact lenses: current achievements, challenges, and perspectives

“…Contact lenses are minimally invasive, and electronic lenses will offer real-time, non-traumatic biomarker probing, among many different possible applications. It should be emphasized, however, that whereas reports in popular media concerning smart contact lenses are stunningly impressive [1][2][3][4], actual, bona fide contact lens-based gadgets presented in the scientific literature are still quite far from real practical applications [5][6][7][8][9][10][11]. As the name implies, electronic circuitry relies on electric power, and even though the power demands of state-of-the-art micro-or even nano-electronics are minimal, some power is nonetheless needed.…”

“…While there is not much to say about the first approach [5,8,9], which is obviously a reasonable approach for scientific studies but certainly inappropriate for an end user, the second group is very diverse and includes over-the-air (OTA) electric power delivery [2,6,8,11], as well as solar [7] and electrochemical cells [12,13].…”

“…Consequently, the available pre-flight information on 'smart' or 'bionic' lenses refers to OTA power securement, based on radio frequency coupling in particular [2,6,8,11]. Other OTA protocols, not specifically involving lenses, draw on infrared and ultrasound.…”

“…Recognizing the problems with a discontinuous power supply, conventional capacitors were actually already inbuilt into electronic contact lenses with OTA power delivery [6,11]. In its present embodiment, the charge-storing FC, or alternatively, the self-charging capacitor, is built from high-end nanomaterials in a monocoque fashion, that is, the FC electrodes also serve as the capacitor conductors [33,34].…”

Design and Implementation of Potentiostat with Standalone Signal Generator for Vanillylmandelic Acid Biosensors

“…Previously, many researchers devoted themselves to developing single-chip potentiostats to reduce the chip's size. Turner et al first presented a basic complementary metal-oxidesemiconductor (CMOS) integrated potentiostat, (4) Liao et al presented a CMOS potentiostat with glucose sensor for wireless contact-lens tear glucose monitoring, (5) Nazari et al proposed a 96-channel potentiostat for on-die microsensors, (6) Zuo et al proposed a low-power 1 V potentiostat for glucose sensors, (7) Kim and Ko proposed a 1.2 V analog front-end integrated circuit (IC) for glucose monitoring, (8) and Huang et al proposed ICs for the monolithic implementation of a voltammeter potentiostat with a large range of dynamic current (5 nA to 1.2 mA) and short conversion time (10 ms). (9) However, the above potentiostats cannot be directly used because they need to be integrated with other devices as a complete system for actual applications.…”