The influence of refractive index change on a micro-cantilever bio/chemical sensor system based on optical lever read-out method

The refractive index of the liquid was speculated to influence the detection signal in a micro-cantilever biosensing system based on optical lever read-out method. In this paper, we present the theoretical analysis of the influence of refractive index change on the detection signal. The results showed that the detection signal of system was greatly impacted by the change of the liquid refractive index as small as 10−3. By conditioning the experimental parameter such as incidence angle of laser, angle between micro-cantilever and liquid surface, the effect can be effectively eliminated without reducing the detecting sensitivity of the system. The theoretical results were validated by the experiments.