Fiber-optic chemical and biochemical probes based on localized surface plasmon resonance

A novel reflection-based localized surface plasmon resonance fiber-optic probe for chemical and biochemical sensing is reported. The sensor is based on intensity measurement of the internal reflected light at a fixed wavelength from an optical fiber where the extinction cross-section of self-assembled gold nanoparticles on the unclad portion of the optical fiber changes with different refractive index of the environment near the gold surface. The reflection-based localized surface plasmon resonance fiber-optic probe has been shown to be capable of direct sensing of the “spectroscopically silent” Ni2+ ion and label-free detection of streptavidin and staphylococcal enterotoxin B at the picomolar level.