Dual-mode DNA detection and hybridization using gold nanoparticles: integrating label-free SERS and MEF to evaluate conformational changes

Detecting unmodified DNA label-free is challenging, but Surface-Enhanced Raman Spectroscopy (SERS) and Metal-Enhanced Fluorescence (MEF) offer promising solutions. We used colloidal gold nanoparticles (AuNPs) to address reproducibility issues in SERS analysis, attaching polyA strands with a thiol group and Cy5 fluorophore to AuNPs. Binding target molecules, such as polyT aptamers, caused conformational shifts that reinstated fluorescence. We tested various lengths and concentrations of polyA and polyT, with promising results confirmed by changes in fluorescence lifetime, enabling real-time detection and quantification of DNA hybridization with ease.