Analytical Characterization of Label-Free Immunosensor Subsystems Based on Multi-Walled Carbon Nanotube Array-Modified Gold Interface

In the present work, we report characterization studies of antigen(Ag)-antibody (Ab) interaction based on the multi-walled carbon nanotube array-modified gold electrode for label-free electrochemical immunosensor. -COOH functionalization of MWCNT was suggested by FTIR spectroscopy. Images from atomic force microscopy (AFM) and RAMAN spectroscopy confirmed the interaction of Ab on the gold interface based on the MWCNT array. A cyclic voltammetric study exhibited a linear response in phosphate buffered saline (PBS) solution including 1mM K3Fe (CN) 6 at pH 7.4 with PSA concentrations over a range of 2 to 40 ngmL-1, and a calculated detection limit of 0.56 ngmL-1.