A Wireless Optoelectronic Neuroscience Platform for Chronic Fluorescence Sensing in Freely Behaving Rodents

Area of Science:

• Neuroscience
• Biomedical Engineering
• Electrical Engineering

Background:

• Fiber-based biophotometry is crucial for monitoring neuronal activity.
• Conventional systems are tethered, limiting animal movement and experimental scope.
• A need exists for miniaturized, wireless solutions for in-vivo neuroscience research.

Purpose of the Study:

• To present a novel head-mountable wireless fiber biophotometry microsystem.
• To enable detection of fluorescent signal fluctuations correlated with neuronal activity.
• To overcome limitations of tethered systems for in-vivo animal studies.

Main Methods:

• Integration of an LED, custom CMOS biosensor, multimode fiber, MCU, and wireless transceiver.
• Development of a novel optoelectronic biosensor combining a low-noise front-end and a 2nd order continuous-time Sigma-Delta modulator (CTSDM).
• Implementation of the CMOS biosensor in 0.18-μm technology within a 3D-printed housing.

Main Results:

• The microsystem successfully detects fluorescent signal fluctuations indicative of neuronal activity.
• The custom CMOS biosensor achieves high sensitivity and energy efficiency (41 μW power consumption).
• The system demonstrates a peak dynamic range of 86 dB with a 50 Hz bandwidth at 20 kS/s.

Conclusions:

• The developed wireless microsystem offers a compact and effective solution for fiber biophotometry.
• This technology facilitates high-sensitivity, energy-efficient in-vivo recordings in freely moving animals.
• The new interface opens new possibilities for advanced neuroscience research.