A simple self-assembled methodology relying on a thin block copolymer film of poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) to immobilize gold nanoparticles (AuNPs) on the optical fiber substrate was demonstrated for localized surface plasmon resonance (LSPR) sensing. The procedure was applied to different sizes of AuNPs from 10 to 92 nm, forming a monolayer of AuNPs with high uniformity and density. The resonance wavelength and refractive index sensitivity was increased with larger nanoparticle diameter and smaller gap between particles. This phenomenon was shown with the general agreement of experimental measurements with the simulations performed using FDTD solutions. In comparison with other AuNP deposition methods using (3-aminopropyl) trimethoxysilane (APTMS) and polyelectrolytes, the sensitivity and figure of merit for the PS-b-P4VP templating method was found to be 3-fold better than the other two methods, a consequence of the smaller gap between particles and the presence of only a few AuNP aggregates. In addition, this highly sensitive fiber sensor was utilized as a compact and low-cost biosensor for the immunoassay of the interaction between human IgG and anti-human IgG.

Optical fiber based localized surface plasmon resonance biosensor prepared by self-assembled gold nanoparticles on block copolymer monolayer

256th National Meeting (2018)

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