Noise analysis and sensitivity enhancement in immunomagnetic nanomechanical biosensors

Kutay Icoz, Purdue
Brian D. Iverson, Purdue
Cagri Savran, Birck Nanotechnology Center and School of Mechanical Engineering, Purdue University

Abstract

We report noise and detection limitations in cantilever-based immunomagnetic biosensors. A differential cantilever system with sensing and control arms was used whereby the control arm was passivated with bovine serum albumin
BSA and the sensing arm was functionalized with biotin-BSA. Streptavidin-coated magnetic beads were exposed to cantilever arms. An oscillatory magnetic field induced a magnetic force on the beads which caused a relative deflection of the sensing arm. Increasing the excitation frequency suppressed the 1/ f noise by 100-fold, resulting in a deflection resolution of 0.065 Å in air.