Affinity cantilever sensors for cardiac diagnostics

Abstract

Cardiac problems are on the rise in the Indian sub-continent due to the changing life styles and food habits. Acute Myocardial Infraction (AMI) is becoming a major concern. In this paper, we report the development of affinity cantilever based sensors for the detection of AMI with optical and electrical readouts. We designed, simulated and fabricated these cantilevers with various micro fabricated materials such as silicon dioxide, silicon nitride and SU-8. Thin films such as silicon nitride and p-type polysilicon are deposited using hot wire CVD technique. For electrical detection, p-type polysilicon was used as a piezoresistive layer. The mechanical and electrical performance parameters of these cantilevers were investigated using Atomic Force Microscope (AFM) set-up. The top surface of these cantilevers was selectively immobilized with the antibodies. Following this, antibody specific antigens were allowed to react with the cantilever surface in the liquid cell of AFM set-up for the optical detection. For electrical signal detection, microcontroller based signal conditioning and digital readout circuit was developed.