Estimation of diaphragm deformation induced by molecuar adsorption on mems optical interferometric biosensor

We have recently developed a surface stress sensor based on a MEMS FabryPerot interferometer integrated with a photodiode, which utilizes the nonlinear optical transmittance change in the FabryPerot interference to enhance the sensitivity of the surface stress. Parylene-C was used as a deformable membrane in the sensor because of negligible residual stress and low Young's modulus of 2.8 GPa, which provides a large deformation with respect to molecular adsorption. After immobilization of 2-pg anti-BSA on the FabryPerot sensor, we measured about 50 nm deformation by surface profiler and reflection spectrum.