Protein Based Localized Surface Plasmon Resonance Gas Sensing

We apply the localized surface plasmon resonance（LSPR） of gold nanoparticles（GNPs） covalently coupled with cytochrome c（cyt c） to create a nanobiosensor for detecting hydrogen sulfide（H2S） in the range of 15-100 ppb.Monolayer formation of GNPs on glass surface functionalized with 3-aminopropyltrimethoxysilane（APTMS） is performed for fabricating a chip-based format of the optical transducer.By chemical introduction of short-chain thiol derivatives on cyt c protein shell via its lysine residues,a very fast self-assembled monolayer（SAM） of cyt c is formed on the GNPs.Significant shifts in the LSPR peak(△λ;) are observed by reacting H;S with cyt c.Results show a linear relationship between △λ;and H;S concentration.Furthermore,shifts in the LSPR peak are reversible and the peak positions return to their pre-exposure values once the H;S is removed.The experimental results strongly indicate that the protein based LSPR chip can be successfully used as a simple,fast,sensitive and quantitative sensor for H;S detection.