Fully Packaged Nonenzymatic Glucose Microsensors With Nanoporous Platinum Electrodes for Anti-Fouling

CMOS integrable nonenzymatic glucose microsensors with nanoporous platinum (Pt) working and counter electrode (WE/CE) were first fabricated, packaged, and characterized with biocompatible Nafion and hydrophilic polyurethane (HPU) membrane materials. Optimal packaging material and its processing condition for these nonenzymatic sensors were investigated. The optimally packaged glucose microsensor was evaluated in human blood plasma solution for checking its biocompatibility and commercial applicability. The fabricated microsensors with nanoporous Pt WE/CE had a sensitivity of 7.75 muA mM ^-1 cm ^-2. The packaged microsensor with Nafion membrane had better performance characteristics than packaged one with HPU. The packaged microsensor with 1:6 ratio of Nafion to ethanol exhibited a sensitivity of 0.83 mu A mM^-1 cm^-2 and stable current change in the human blood plasma solution, while the current response of nonpackaged microsensor was rapidly saturated because adsorption of various proteins and cells as expected. These data indicate that the packaged nonenzymatic microsensor with biocompatible Nafion membrane is promising and strongly applicable for in vitro and in vivo glucose monitoring systems.