A disposable “intelligent mosquito” with a reversible sampling mechanism using the volume-phase transition of a gel

A disposable microanalysis system that imitates a mosquito was fabricated using micromachining techniques. The essential components were a sampling mechanism, a microscopic needle, and a micro glucose sensor. The volume-phase transition of poly(N-isopropylacrylamide) gel was used to construct a reversible sampling mechanism with the help of the elastic force of a silicone rubber layer. The sampling mechanism could repeatedly pump an external sample solution into and out of the flow channel through a microscopic needle of 50 μm diameter at 37 and 30 °C, respectively. Standard solutions of glucose were successfully introduced into the system, and the on-chip micro glucose sensor showed a distinct response to the sampled glucose solution. The 90% response time was from 30 to 40 s. A linear calibration curve was obtained for glucose concentrations up to 8 mM.