Real-Time SERS-Tracking of Adenine-Gold Charge Transfer Complex Formation on Nano-Cavities Shaped Plasmonic Crystals

Understanding binding of DNA bases with gold surfaces is crucial for designing reliable tools in biosensing technology and organic-based electronics. Herein, we discuss an application of quasi periodic plasmonic nanocavities fabricated by a top-down method to study adenine interactions with gold surfaces. We report plasmon-mediated homogenous catalysis of adenine-gold complex formation, when adenine is deposited onto surfaces in different ways. In particular, we elucidate how additional information can be obtained by adsorbate irradiation with laser far from resonant conditions with a low-localized, high-integral field substrate. A comparative study between mono- and multilayers on gold is proposed, offering a solution to the controversial question of adenine orientation on gold surfaces by revealing charge transfer complex formation during realtime surface enhanced Raman scattering tracking. Additionally, the designed nanocavity-based plasmonic substrates exhibit a high sensitivity with a limit of detection ? 25 nM.