Micro-Weighing Based Biosensor with Adaptive Interferometry

Abstract

In this work, an adaptive holographic interferometer was implemented for the measurement of a micromechanical oscillator frequency. A silicon micro-cantilever mounted on a piezoquartz plate was used as the sensing element. Out-of-plane vibrations of the cantilever were excited using a sinusoidal electrical signal. The cantilever vibrations were measured with the adaptive interferometer using two waves coupling in a semi-insulating photorefractive CdTe:V crystal. In the experiment, the mass of absorbed molecules of bovine serum albumin (BSA) was measured at various concentrations of water solution. The biosensor demonstrated the ability to measure the concentration of BSA in water solutions with a concentration of 0.2 mg/mL. The result shows the possibility of using adaptive interferometry to detect the vibration of micromechanical sensors and the potential prospects for building biosensors based on them.

Keywords

• biosensor
• micromechanical oscillator
• laser biosensor
• holographic interferometry
• mass sensor
• adaptive interferometer