Thermal Analysis of Light Source for Optogenetics Experiments

摘要

In the last decade, light has been increasingly used as an innovative optical stimulation tool for therapeutic and diagnostic neuronal applications. Light-emitting diodes (LEDs) have emerged as a suitable light source. Such implantable systems include small-dimensional diodes as light sources for nerve stimulation in tandem with neural electrodes. All such devices generate a huge amount of heat which may limit their functionality and characteristic behaviour. Heat generated, if not properly engineered to dissipate through the design, may cause serious damages to biological tissue especially in the case of brain implants. The main purpose of the proposed project is to analyse the thermal behaviour of Optrodes operating in the brain environment and thermal management techniques for such a device. The work started with the analysis of heat dissipation from an LED and methods to insulate the brain tissues. Finite element method simulation is done to investigate thermal characteristics of implantable Optrodes. In order to verify the simulated results, an Optrode structure is developed on a standard substrate. The temperature of the Optrode is measured experimentally in operating mode in environmental conditions similar to brain tissues. The results from simulation, experiment, and analytical calculations are compared for validation. Finally, optical characteristics of LED are measured to correlate the thermal behaviour of the system. From the results obtained, a technically feasible thermal management system for such an Optrode design is suggested.