Graphene-mediated Surface Enhanced Raman Spectroscopy for Detection of Biomolecules and DNA Hybridization

In this work, we prepared graphene-mediated surface-enhanced Raman scattering (G-SERS) substrates comprising few-layer graphene nanosheets decorated gold and silver nanoparticles for bio-nanotechnology. Raman scattering and particularly, SERS is a surface-sensitive spectroscopy technique useful for rapid and precise identification of biological molecules, industrially relevant chemical dyes at ultralow concentration and DNA hybridization due to the enhanced signal by several orders of magnitude on SERS-active surfaces. While SERS technology is based on metal nanoparticles, which generates localized surface plasmon resonances, diameter and interparticle gap on graphene supports offer an advance toward sensitive G-SERS substrates via localized hybridization at the interface. We used thermal reduction to produce few-layer functionalized graphene and wet chemistry for size tunable gold and silver nanoparticles for strategic G-SERS platforms. High-throughput arrays (or ‘biochips’) are developed as well as sandwiching gold and silver nanoparticles and few-layer graphene for cascaded signal amplification to differentiate among nucleotide bases (adenine; A, thymine; T, cytosine; C, guanine; G), DNA hybridization and to detect beta-carotene and malachite green chemical dye.