Open flow microperfusion: approach to in vivo glucose monitoring.

A slow flow of liquid over the working tip of a classical glucose needle electrode allows a significant reduction in surface fouling with minimal sample dilution. The fluid flow technique enables relatively drift-free in vivo operation for up to four hours (electrode responses in vitro following explanation of the device after a 4 h monitoring period are within +/- 5% of original values), exhibits a close correlation with blood glucose levels and is unique in requiring no in vivo calibration.