Micro-wing and pore design in an implantable FPC-based neural stimulation probe for minimally invasive surgery

This paper presents a bipolar porous probe for implantable nerve stimulation treatment utilizing minimally invasive surgery. The probe´s design features micro-wings and pores for cell growth that promote long term fixation in the body. Two recording pairs detect whether cells grow into the pores, and one pair of stimulating pads stimulates the target nerve. The probe is composed of three layers: two SU-8 layers and one flexible printed circuit (FPC) layer. Results show that SU-8 films can increase the product of the area moment of inertia and Young´s Modulus by 9.04% from 5.86×10^-6 N·m² to 6.93×10^-6 N·m² and that micro-wings can increase the force of fixation by 38.58% from 0.114 N to 0.158 N. From the impedance test, the impedance of the pores in gelatin is shown to be lower than the ones in air, demonstrating that the two recording pairs are promising for detecting cells growth.