Enhancing Nonfouling and Sensitivity of Surface-Enhanced Raman Scattering Substrates for Potent Drug Analysis in Blood Plasma via Fabrication of a Flexible Plasmonic Patch

Surface-enhanced Raman scattering (SERS) is an ultrasensitive analytical technique, which capable of providing high specificity; thus, it can be used for toxicological drug assay (detection and quantification). However, SERS-based analysis directly in human biofluids requires mitigation fouling nonspecificity effects that commonly appeared from unwanted adsorption endogenous biomolecules present (e.g., blood plasma serum) onto the SERS substrate. Here, we report a bottom-up fabrication strategy to prepare substrates, first, by functionalizing chemically synthesized gold triangular nanoprisms (Au TNPs) with poly(ethylene glycol)-thiolate solid state avoid protein second, generating flexible plasmonic patches enhance sensitivity via formation high-intensity electromagnetic hot spots. Poly(ethylene glycol)-thiolate-functionalized Au TNPs form show twofold-improved signal-to-noise ratio comparison triethylamine (TEA)-passivated TNPs. Furthermore, patch displays enhancement factor 4.5 ×107. Utilizing Langmuir model, determine constant drugs two different surface ligands observe molecules display stronger affinity glycol) than TEA. Our density functional theory calculations unequivocally support interaction between moieties. universality detection demonstrated cocaine, JWH-018, opioids (fentanyl, despropionyl fentanyl, heroin) binary mixture (trace amount fentanyl analyses. We demonstrate applicability selective at picogram/milliliter concentration levels drug-of-abuse patients' plasma. The calculated excellent agreement values determined using paper spray ionization mass spectrometry technique. believe would widely applicable any nanostructure chemical sensing clinical toxicology therapeutic monitoring.