DYNAMIC PLASMON ENHANCED RAMAN SCATTERING IN BIOMOLECULES AND WHOLE BLOOD ON Ag NANOPARTICLES

Abstract

Surface enhanced Raman spectroscopy (SERS) is a highly sensitive method to characterize
biomolecules down to the single molecule level. Previously, various methods have been employed to
fabricate nanoparticles of Ag and Al to generate plasmon systems for enhanced Raman scattering.
Here, we employ a simple method to fabricate Ag nanoparticle surfaces for enhanced Raman scattering. Silk fibroin was used as a paradigm for biomolecules. Dynamic plasmon enhancement of
Raman spectra of silk fibroin films was observed. Different runs of the same samples after exposure
to the laser light for a certain period of time show dramatic changes in intensities of the vibrational
bands. Relative intensities as well as number of the resolved bands are significantly differ from
each other within spectra. Possible mechanism of such selective enhancement of various bands and
their dynamic nature are discussed. Ag nanoparticle system was also tested on complex body fluid
system, whole blood. Preliminary data indicate that localized plasmons created by Ag nanoparticles enhance Raman bands by various degrees. Feasibility to use the plasmon enhanced Raman
spectra of the whole blood for diagnostics is discussed.
Keywords: surface enhanced Raman spectroscopy, nano-plasmon, silk fibroin, Ag nanoparticles