Fast mechanical biosensing in liquid using mems Fabry-Perot interferometric surface-stress sensor

We developed an optical interferometric surface-stress sensor which utilizes the nonlinear optical transmittance change in the Fabry-Perot interference to enhance the sensitivity of the surface-stress, integrated with a microfluidic channel for fast biosensing. A 30-μm-thick photosensitive dry film resist was laminated on the sensor, followed by a standard photolithography to form microfluidic channel. During the liquid supplying to the sensor, no liquid leakage into nano cavity was observed because output photocurrent shows constant. Photocurrent change of 8 nA was obtained when an anti-bovine serum albumin (BSA) with concentration of 100 ng/ml was injected with flow rate of 1 μl/min. Response time was successfully improved to be several tens of seconds.