Thermal Analysis of Light Source for Optogenetics Experiments

ABSTRACT

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.

KEYWORDS:

• Biological neural networks
• Implants
• Light-emitting diodes
• Medical Packaging
• Optogenetics
• Optrodes
• Thermal management of electronics

Acknowledgements

The authors sincerely thank the support of the IMOS team, University of Magdeburg, for contribution in supporting facilities.

Additional information

Funding

The authors also thank Pralhad P. Chhabria Research Center, Pune for their financial support for travel.

Notes on contributors

Rabinder Henry

Rabinder Henry is Director at Pralhad P. Chhabria Research Center, Pune. He was the Associate Dean-HOD & Professor of School of Interdisciplinary Science & Technology at I²IT from 2006 to 2012. He holds a Master of Science degree in RF & microwave engineering, photonics and medical systems from Technical University of Dresden and University of Magdeburg. He has worked with Fraunhofer Institute for Photonics Microsystems, Institute for Electron Devices and Integrated Circuits, Dresden and Helmholtz Zentrum Rossendorf.

Velmathi Guruviah

G Velmathi is currently working as professor in the School of Electronics Enginnering in VIT, Chennai Campus. She got her PhD from the Indian Institute of Science in the field of MEMS, Gas Sensor and VLSI design. She has published many national and international conference papers. She has two patents and few awards like best teacher award to her credit. She has two ongoing projects funded by DST for the benefits of disabled elderly. Email: [email protected]