A wireless-implantable microsystem for continuous blood glucose monitoring.

A remotely powered implantable microsystem for continuous blood glucose monitoring is presented. The microsystem consists of a microfabricated glucose biosensor flip-chip bonded to a transponder chip. The transponder chip is inductively powered by an external reader with a 13.56-MHz carrier. It then measures the output signal of the glucose biosensor and transmits the measured data back to the external reader using load-shift keying (LSK). The microsystem has a volume of 32 mm(3). The procedures for the microfabrication of the glucose sensor and the assembly of the microsystem are described along with the description of the circuit blocks of the transponder chip. The transponder chip has been fabricated with the TSMC 0.18-mum CMOS process and has a total area of 1.3 x 1.3 mm(2). The chip can measure the sensor output current ranging from 1 nA to 1 muA with less than 0.3% nonlinearity error, provided that the amplitude of the received RF signal is higher than 2.6 V; the circuit consumes a total current of about 110 muA.

A Low-Light CMOS Contact Imager With an Emission Filter for Biosensing Applications.

In this paper, a fully functional low light 128 X 128 contact image sensor for cell detection in biosensing applications is presented. The imager, fabricated in 0.18 mum CMOS technology, provides low-noise operation by employing both a modified version of the active reset (AR) technique and a modified version of the active column sensor (ACS) readout method. High-sensitivity, low noise performance of the presented sensor is well-suited for fluorescence imaging. For this purpose, an emission filter was fabricated and integrated with the sensor. The filter was fabricated using PDMS and Sudan II Blue dye mix, spin-coated and deposited in a class 1000 clean room. The designed filter is suitable for excitation at wavelengths below 340 nm and emission at 450 nm and above. The fabricated imager architecture and operation are described, noise analysis is presented and measurements from a test chip are shown. Experimental results using live neurons from the pond snail, Lymnaea stagnalis, and fluorescence polystyrene micro-beads prove the functionality of the fabricated system and indicate its biocompatiblity.

VLSI neural system architecture for finite ring recursive reduction.

The use of neural-like networks to implement finite ring computations has been presented in a previous paper. This paper develops efficient VLSI neural system architecture for the finite ring recursive reduction (FRRR), including module reduction, MSB carry iteration and feedforward processing. These techniques deal with the basic principles involved in constructing a FRRR, and their implementations are efficiently matched to the VLSI medium. Compared with the other structure models for finite ring computation (e.g. modification of binary arithmetic logic and bit-steered ROM's), the FRRR structure has the lowest area complexity in silicon while maintaining a high throughput rate. Examples of several implementations are used to illustrate the effectiveness of the FRRR architecture.