A Wireless Fiber Photometry System Based on a High-Precision CMOS Biosensor With Embedded Continuous-Time Modulation

Fluorescence biophotometry measurements require wide dynamic range (DR) and high-sensitivity laboratory apparatus. Indeed, it is often very challenging to accurately resolve the small fluorescence variations in presence of noise and high-background tissue autofluorescence. There is a great need for...

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Bibliographic Details
Published in:IEEE transactions on biomedical circuits and systems 2018-06, Vol.12 (3), p.495-509
Main Authors: Khiarak, Mehdi Noormohammadi, Martianova, Ekaterina, Bories, Cyril, Martel, Sylvain, Proulx, Christophe D, De Koninck, Yves, Gosselin, Benoit
Format: Article
Language:English
Subjects:
Background noise
Biosensing Techniques - instrumentation
Biosensing Techniques - methods
Biosensors
Brain
CMOS
Detection
Dynamic range
Embedded systems
Energy efficiency
Fluorescence
Hardware
Head
Humans
Laboratory equipment
Linearity
Noise
Photometry
Photometry - instrumentation
Photometry - methods
Power consumption
Power efficiency
Sensitivity
Sensors
Wireless Technology - instrumentation
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Summary:Fluorescence biophotometry measurements require wide dynamic range (DR) and high-sensitivity laboratory apparatus. Indeed, it is often very challenging to accurately resolve the small fluorescence variations in presence of noise and high-background tissue autofluorescence. There is a great need for smaller detectors combining high linearity, high sensitivity, and high-energy efficiency. This paper presents a new biophotometry sensor merging two individual building blocks, namely a low-noise sensing front-end and a order continuous-time modulator (CTSDM), into a single module for enabling high-sensitivity and high energy-efficiency photo-sensing. In particular, a differential CMOS photodetector associated with a differential capacitive transimpedance amplifier-based sensing front-end is merged with an incremental order 1-bit CTSDM to achieve a large DR, low hardware complexity, and high-energy efficiency. The sensor leverages a hardware sharing strategy to simplify the implementation and reduce power consumption. The proposed CMOS biosensor is integrated within a miniature wireless head mountable prototype for enabling biophotometry with a single implantable fiber in the brain of live mice. The proposed biophotometry sensor is implemented in a 0.18- CMOS technology, consuming from a 1.8- supply voltage, while achieving a peak dynamic range of over a 50- input bandwidth, a sensitivity of 24 mV/nW, and a minimum detectable current of 2.46- at a 20- sampling rate.
ISSN:1932-4545
1940-9990
DOI:10.1109/TBCAS.2018.2817200