Periodic and Dynamic 3-D Gold Nanoparticle-DNA Network Structures for Surface-Enhanced Raman Spectroscopy-Based Quantification

The enhancement factor of gold nanoparticles linked by DNA in a three-dimensional (3-D) network structure was evaluated as 1.12 x 10(7) and shown to be greater than a two-dimensional (2-D) array by a factor of similar to 10, possibly due to the dimensional expansion of resonance and periodicity of the so formed structures. Uniform and higher level of enhancement was possible from these DNA linked gold nanoparticle networks because of the matching of the resonant condition and the excitation wavelength (785 nm) to enable dynamic quantification of analytes by surface-enhanced Raman spectroscopy (SERS). The structure was first validated by obtaining a SERS measurement of 4-mercaptopyridine; then, rhodamine B was used as a test analyte to quantify the dye up to nanomolar concentrations using the proposed 3-D network structures dynamically in a liquid system. Since these constructs can be easily fabricated, we envision its application in in vitro quantification and intracellular studies in the near future.