Fabrication of Implantable Flexible Electrodes Based on Patternable Platium Nanowire and Poly Dopamine Layer

Abstract

A novel implantable flexible electrode array based on platinum nanowire (PtNW) was fabricated using poly dopamine (PDA) as the buffer layer and patterned by micro contact printing $(\mu\mathrm{CP})$ technique. The biocompatible PDA film was selectively grafted on the flexible polyimide (PI) substrate patterned by $\mu \mathrm{CP}$ as the adhesive layer for the in situ electroless deposition of PtNW. As-fabricated PDA/PtNW layer can greatly reduce the impedance (1 kHz) by ~90% compared with the conventional Ti/Pt thin film deposited by sputtering. The adhesion between PDA/PtNW or Ti/Pt metal layer and PI was evaluated using ultrasonic attack and twist fatigue test. The results showed that PDA was very effective as the bioinspired adhesive layer between polymer and metal by significantly enhance the structure and impedance stability when suffering mechanical stress. These achievements can be of great interest for robust flexible electronics for implanted or wearable applications.