Localized surface plasmon resonance-based label-free biosensor for highly sensitive detection of dopamine.

Localized surface plasmon resonance (LSPR) is the phenomenon that is observed on specific metal nanoparticles (NPs) like Au, Ag which can be used for sensitive detection for many kinds of biomaterials. Dopamine (DA) is a typical neurotransmitter considered as indicator of some neural diseases. Due to its small size, it is very difficult to detect DA at low concentrations directly and sensitively with conventional sensing techniques. In this research, we propose a DA detection sensor based on LSPR phenomenon. Electrochemical deposition technique was used to make LSPR substrates, where Au NPs were electrochemically deposited on ITO glasses and these substrates showed optical characteristic of LSPR phenomenon. Different concentrations of DA solution were deposited on antibody immobilized LSPR substrates. With additions of increasing concentrations of DA, LSPR peak intensity was increased linearly. These results could be applied to many fields of clinical trials for diseases caused by small molecules.