Laser biosensor based on micromechanical oscillator

摘要

We present laser microweight biosensor based on the adaptive holographic interferometer. The sensing element of thesensor is gold coated silicon microcantilever with dimensions of 210×40×5 μm~3. Biomolecules of the interest beingattached to the cantilever increase its mass which in its turn leads to decreasing the cantilever resonance frequency. Thefrequency shift of the detected signal is directly proportional to the total mass of adsorbed molecules. Cantileveroscillations are detected by the adaptive holographic interferometer based on two-wave mixing in a photorefractive CdTecrystal. For measuring the concentration of biological molecules dissolved in water the cantilever was installed in acuvette which contains the solution. In the experiment, adsorbed molecules of BSA (Bovine Serum Albumin) with totalmass of 3.1 ng were detected and weighted.