An interventional flexible microneedle with three-electrode system on the capillary for continuous glucose monitoring and drug delivery

A three-electrode system has been fabricated and integrated on the cylindrical polymer capillary surface by micromachining, which could be used as an interventional flexible microneedle for glucose sensor application in future. A UV-lithography system is improved to realize for the first time the multi-layer alignment exposure for cylindrical polymer capillary substrates based on our previous home-made lithography equipment. The ±1μm alignment precision has been realized on the polymer capillary surface with 330μm outer-diameter, on which the three-electrode structure consisting of two platinum electrodes and one Ag/AgCl reference electrode has been fabricated. The microneedle prototype with integrated three-electrode structure has been also characterized in 1mol/L KCl and 0.02mol/L K₃Fe(CN)₆ mix solution for obtaining its corresponding cyclic voltammetry curve. It shows that the prepared three-electrode system has a good redox property.