METALLIZED POLYMER FIBERS AS LEADWIRES AND INTRAFASCICULAR MICROELECTRODES

We have developed a process for producing fine, very flexible microwir es suitable for use as small signal leadwires or nerve electrodes. The process incorporates metallization of high-performance monofilament p olymer fibers to yield electrically conductive fibers with greatly imp roved flexibility over solid metal wires of similar strength. The meta llization layers are produced by serial vacuum deposition of a 0.3 mu m thick coating of three metals, titanium-tungsten (Ti/W), gold (Au), and platinum (Pt), onto monofilament, poly-p-phenyl-terephthalate aram id fibers (Kevlar(R)). The metallized fibers are then insulated with a n approx. 1 mu m thick layer of silicone elastomer. The result is a mi crolead with high electrical conductivity (linear resistance = 30 Ohm/ cm), desirable interfacial properties, excellent mechanical stability and extremely high flexibility. These physical characteristics are app ropriate for application as signal leadwires or recording/stimulating electrodes where small size and high flexibility are paramount. In thi s paper we report on the electrical and mechanical properties of these metallized fibers and demonstrate their use as intrafascicular electr odes for recording multi-unit neural activity in feline peripheral ner ves.