SINGLE-WALLED CARBON NANOTUBE (SWCNT) BASED CHEMIRESISTIVE/FET BIOSENSOR FOR THE DETECTION OF BIOSENSOR FOR THE DETECTION OF BIOMARKERS

Abstract

Field Effect Transistor (FET) based biosensor is a very specific and ultrasensitive, label- free chemiresistive biosensor. Here, SiO2/Si wafer (FET) with gold microelectrode (Source and Drain electrode) was aligned with SWCNT by dielectrophoresis process. It was then modified with 1- Pyrenebutaric acid N-hydroxysuccinimide Ester (PyBt-NHS-Ester) which is a cross- bilinker. It was further passivated with 6-methylcapto-1-hexanol (MCH) to block the non-specific sites. Antibody C - reactive protein (CRP) with the concentration of 100 ng/mL was then drop-cast onto the modified SWNT. There is a covalent immobilization between PyBt-NHS ester and antibody, anti-CRP. Bovine serum albumin (BSA) was then used to block the non-specific sites at the SWCNT channel. The sensing measurement was performed by monitoring the changes in the current versus voltage (I-V) characteristics of the device on antibody-antigen interaction over SWCNTs channel. The sensing performance of the CNT-device was investigated for antigen (CRP) over the concentration range of 10 ng/mL to10000 ng/mL.