Synthesis of MWCNT Functionalized SiO2 Thin Film for Biosensor Application

The improvement of sensor sensitivity is the quest of every researcher in the recent time, sensor developed using multi-walled carbon nanotubes (MWCNT) has been used in many different applications, and however, the device is not quite sensitive to go for lower concentration in medical diagnostic. Hence, to improve the sensitivity of this device we synthesized MWCNT from a fuel oil waste of power plants. The MWCNT surface morphologies were examined by field emission scanning electron microscopy (FE-SEM), the elemental analysis performed with an energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The electrochemical DNA biosensor was successfully fabricated by depositing polyethyl-eneimine branch (PEI-b) solution via MWCNT on SiO2 electrode. Cyclic voltammetry (CV) was done to study the electrochemical behaviour of the device using potassium hexacyanoferrate characterization on the MWCNT electrode. For a better performance, MWCNT was modified onto SiO2 to enhance the stability and high signal of MWCNT electrode better when PEI-b was used as the binder compared to bare electrode. It shows the highest electrical performance of DNA immobilization and hybridization on MWCNT modified SiO2 surface, hence, this successfully electrochemically and significantly increased the sensitivity of the biosensor.