Sub-5μM Diameter Silicon Microprobe and Silicon Dioxide Microtube Arrays for Low-Invasive In-Vivo Animal Experiments

We report applications of sub-5 μm diameter silicon microprobes and silicon dioxide microtubes fabricated by vapor-liquid-solid method and microfabrication techniques, to use in in-vivo animal experiments. Before animal experiments, electrical impedance and test signal detection via the microprobe electrode were investigated. According to the results, electrical impedance at 1 kHz is approximately 2 MOmega, and microprobe detected the test signals (80 muV_p-p at 1 kHz) in saline solution. For microtube array, liquid flow through the microtube is confirmed at injection pressures of 25-45 kPa to get sub-muL/min flow rates. Finally, the microprobe and the microtube were applied to tibial muscle and sciatic nerves of rats, respectively. From these animal experiments, we could observe the electrical and chemical reactions of muscle and nerves using both sub-5 mum diameter microprobe and microtube successfully.