Controlled Surface Enhanced Resonance Raman Scattering (SERRS) in Biological Environment

Abstract

We report here the use of gold nanoparticle (AuNP) and gold nanostar (AuNS) assemblies modified with oligonucleotides for the detection of target DNA molecules through SERRS. SERS activities of assmblies consisted of 16 nm AuNPs, 30 nm AuNSs and 100 nm AuNSs were compared. Interaction of localized surface plasmon resonance (LSPR) of AuNP and AuNS assemblies were controlled through adjusting the distance between AuNPs/AuNSs which were realized by varying the length of oligonucleotide with various base sequence. Raman spectroscopies were measured with excitation wavelength of 633 nm. It was found that stronger Raman signal was recorded when AuNSs were used while weaker signals were obtained with AuNPs. This may attribute to AuNSs has tip-enhancement effect while AuNPs has no tips on surface, and AuNSs DNA probes can easily detect 10 nM target DNA. We also found that the Raman signal being stronger when the distance between nanoparticles is ∼3 nm than that of ∼6 nm and ∼12 nm. We envisage this study will achieve further insight into the mechanism of SERRS and provide a general approach for the ultrasensitive detection of biomolecules based on SERRS.