Surface-enhanced Raman scattering investigation of bovine serum albumin by Au nanoparticles with different sizes

Background: Surface-enhanced Raman scattering (SERS) has become a useful spectroscopic tool for studying biomolecule structures. The main types of plasmonic substrates used in biological systems are Au nanoparticles (AuNPs), whose surface plasmon resonance depends on the nanoparticle size, morphology, particle interspace, and so on. Methods: In this study, AuNP colloids with different sizes were synthesized and used as the sensors to probe SERS signals of different biomarkers and biomolecules. Results: The results showed that an AuNP colloid of ~50 nm had excellent SERS effects in probing various molecules, and could be preserved for about 3 months with excellent repeatability and reproducibility (RSD <5%) in terms of the probed signal intensity (rhodamine 6G and crystal violet). Meanwhile, the fabricated AuNPs were applied to study the SERS signals and structural information of bovine serum albumin (BSA) in aqueous solution. It was found that SERS could rapidly provide the structural information and vibration characteristics of BSA. Conclusion: It was concluded that biocompatible AuNP colloid may be a promising biosensor in the rapid and label-free detection of biological systems.