A 27-Mbps, 0.08-mm3 CMOS Transceiver with Simultaneous Near-field Power Transmission and Data Telemetry for Implantable Systems.

This paper describes an inductively powered 27-Mbps, 0.08-mm3 CMOS transceiver with integrated RF receiver coils for simultaneous two-way, near-field data telemetry and power transmission for implantable systems. A four-coil inductive link operates at a 27-MHz carrier for power and a 700-MHz carrier for data telemetry with the antennae taking an area of only 2 mm by 2 mm. Amplitude-shift-keying (ASK) modulation is used for data downlink at 6.6 kbps and load-shift keying (LSK) backscattering is used for data uplink at 27 Mbps. The transceiver consumes 2.7 mW and can power a load consuming up to an additional 1.5 mW. Implemented in a 0.18-um silicon-on-insulator (SOI) technology, post-processing steps are used to decrease chip thickness to approximately 15um, making the chip flexible with a tissue-like form factor and removing the effects of the substrate on coil performance. Power harvesting circuitry, including passive rectifier, voltage regulator, RF limiter, ASK and LSK modulator, clock generator, and digital controller are positioned adjacent to the coils and limited to an area of 0.5 mm by 2mm. Complete transceiver functionality of the system has been achieved with overall power transfer efficiency (PTE) of 1.04% through 1 mm of tissue phantom between reader and implant.

Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms.

Despite advances in monitoring spatiotemporal expression patterns of genes and proteins with fluorescent probes, direct detection of metabolites and small molecules remains challenging. A technique for spatially resolved detection of small molecules would benefit the study of redox-active metabolites that are produced by microbial biofilms and can affect their development. Here we present an integrated circuit-based electrochemical sensing platform featuring an array of working electrodes and parallel potentiostat channels. 'Images' over a 3.25 × 0.9 mm(2) area can be captured with a diffusion-limited spatial resolution of 750 µm. We demonstrate that square wave voltammetry can be used to detect, identify and quantify (for concentrations as low as 2.6 µM) four distinct redox-active metabolites called phenazines. We characterize phenazine production in both wild-type and mutant Pseudomonas aeruginosa PA14 colony biofilms, and find correlations with fluorescent reporter imaging of phenazine biosynthetic gene expression.