Towards a multi-wavelength spectroscopy platform for blood characterization and analysis.

Passing multiple light wavelengths through a blood sample makes it possible to investigate the presence and composition of cells, metabolytes and analytes such as blood cells, glucose, lactate and oxygen, providing valuable indications for diagnostic and health monitoring. In this paper, we present a test prototype of a multi-wavelength blood spectroscopy platform integrated with a microfluidic substrate to collect and convey blood samples through a series of micro-LEDs and a photo-detector. This spectroscopy platform is a proof of concept for a system that can collect absorbance and transmittance parameters of blood samples at several wavelengths within the visible and NIR spectrum, and transmit them wirelessly to a base station for real-time calculation and analysis. In-vitro measurements are performed with the proposed prototype with 5 channels covering wavelength from 400 nm to 940 nm A full characterization results of the proposed device are presented.

A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability.

We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm² at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals.