Acousto-optic tunable filter-surface plasmon resonance immunosensor for fibronectin

An acousto-optic tunable filter-surface plasmon resonance (AOTF-SPR) immunosensor based on wavelength-modulation was applied to detect fibronectin by direct, sandwich and colloidal Au-enhanced immunoassay. The design of the wavelength-modulation AOTF-SPR immunosensor is based on fixing the incident angle of light and measuring the reflected intensity of light in the wavelength range spanning 440-790 nm. Fibronectin was determined in the concentration range 2.5-30, 0.5-30, and 0.25-30 μg/mL for direct, sandwich and colloidal Au-enhanced immunoassay, respectively. The results demonstrate that AOTF-SPR biosensor can be applied to direct and enhanced immunoassay of biomolecule.