Label-free detection of melittin binding to a membrane using electrochemical-localized surface plasmon resonance.

Localized surface plasmon resonance (LSPR) and electrochemistry measurements connecting to core-shell structure nanoparticle are successfully exploited in a simultaneous detectable scheme. In this work, the surface plasmon band characterizations of this nanostructure type are initially examined by controlling the core size of the silica nanoparticle and shell thickness of the deposited gold. These results clearly show that when the shell thickness is increased, keeping the core size constant, the peak wavelength of the LSPR spectra is shifted to a shorter wavelength and the maximum of peak intensity is achieved at a particular shell thickness. On the basis of this structure, we present a membrane-based nanosensor for optically detecting the binding of peptide toxin melittin to hybrid bilayer membrane (HBM) and electrochemically assessing its membrane-disturbing properties as a function of concentrations. It will open up the way to detect functionally similar protein toxins and other membrane-targeting peptides with the intension of integrating this chip into a microfluid and expanding it into multiarray format.