Conformational change and biocatalysis-triggered spectral shift of single Au nanoparticles.

Spectral shift of localized plasmon resonance scattering of guanine-rich DNA modified single Au nanoparticles is observed under a dark field microscope equipped with a spectrometer. The spectra continuously red-shift with the conformational change of the guanine-rich DNA upon associating with K(+), hemin and the biocatalytic growth of the polymer. The scattering spectrum of single nanoparticles is proved to be sensitive both to a subtle conformational change and the biocatalysis process. 20 mM K(+) or 100 μM H2O2 can trigger a detectable peak shift. The present study paves a new and efficient way to extract chemical information from micro/nanospace.