An in-plane microneedles used for sampling and glucose analysis

We report here the design, fabrication and experiments of a hollow in-plane microneedle, with which a biosensor is integrated to extract interstitial fluid from skin for glucose measurement. The design of hollow in-plane microneedles leads to a simple fabrication process. Different from common methods for immobilizing enzyme, we use capillary force to immobilize enzyme on the surface of microelectrodes. The experimental results showed a good linearity for the characteristic curve of glucose concentration, when it varies from 0 to 500mg/dl with respect to current signal value. The sensitivity of 0.4238nA was obtained.