Flexible Probe for Electrical Neural Signal Recording

Implantable brain recording devices have provided pivotal contribution in understanding the complex functioning of human brain. However, these devices can be used to its fullest potential only if it can be implanted for long period of time without compromising the functionality. In this paper, we reports on an innovative idea of flexible neural probe which can be implanted into brain tissue which causes minimal immune reaction. The developed probe comprises of recording electrodes sandwiched between polyimide layers backed with bio dissolvable Porosified silicon substrate. By employing different anodization recipes we are able to develop probes with porosities of 50%, 60% and 70%. It took 1-2 weeks for the porous silicon shank to fully dissolve in fluid Phosphate-buffered saline depending on the porosity and design used. We also report on recording electrodes made of platinum and platinum black which correspondingly exhibits impedance of 700 kΩ and 6 kΩ at 1000 Hz. Lowering the impedance without changing the physical diameter of the electrodes will provide improved signal-to-noise ratio.