Novel optical nanobiosensor assembled with silver nanoparticles on gold surface

A novel optical biosensor with gold surface bound silver nanoparticles has been constructed for detection of bio-molecules like antigen, antibody protein and DNA plasmid, which exhibited distinct optical properties of localized surface plasmon resonance (LSPR). The silver colloidal nanoparticles were prepared by using sodium borohydride reduction of silver nitrate and characterized by using UV-vis absorption spectroscopy, transmission electron microscopy (TEM), and cyclic voltammetry (CV), indicating that the silver colloidals were pure, sphere-shaped and narrow-dispersed size distribution with a diameter of 10 plusmn 0.5 nm. The silver nanoparticles were well assembled on the gold surface. It caused 3.08 nm of red shift in the peak wavelength (lambda
_max
) of LSPR spectrum for the nanosensor exposed to c-Myc (3C7) mouse monoclonal IgG and 3.36 nm of red shift to the corresponding antibody by the immuno-reaction subsequently. The LSPR nanobiosensor has been successfully applied to recognition of a DNA plasmid of pCMV-Myc Mammalian Expression Vector.