Live Demonstration: An Energy-Efficient CMOS Biophotometry Sensor Interface

Implantable wireless fiber biophotometry is one of the most effective technique to monitor specific cell types through Ca 2+ fluorescence sensing in live animals by avoiding fiber tethering and risks of breakage and injury which can occur in conventional apparatus. This demonstration will show the visitors a novel low-power, light-weight, and minimally invasive wireless optoelectronic interface enabling chronic brain fiber biophotometry in freely moving laboratory mice. The proposed device incorporates a custom integrated CMOS biosensor and off-the-shelf optical and electronic components such as a wireless transmitter, a LED as excitation light source, a microprocessor, and a miniaturized 3D-printed housing. The CMOS biosensor includes a two-step analog-to-digital converter (ADC) with a noise cancellation scheme enabling wide dynamic range and high-energy efficiency photocurrent quantization. A fiber biophotometry head-mountable 3D-printed housing holds in place the optical and electronic components and allows the utilization of a single mutlimode fiber to convey the excitation light and to collect the evoked fluorescence light.