Spatially reinforced nano-cavity array as the SERS-active substrate for detecting hepatitis virus core antigen at low concentrations

Proteomic analysis of biological specimens is of the utmost importance in disease monitoring and containment systems. However, current methodologies require time-consuming incubation steps to obtain clearly isolated target species. To reduce the diagnostic procedures, spectroscopy technologies with the enhanced signal intensity on the target molecules have been growingly developed. In this work, surface enhanced Raman scattering (SERS) technique employed fingerprints for sensing Raman-active molecules. Spatially reinforced Au nano-cavity array (SR-nAu) samples with a reduced tip-to-tip displacement are SERS-active and can be used to recognize bovine serum albumin (BSA), hepatitis B virus core antigen (HBV-cAg), and hepatitis C virus core antigen (HCV-cAg) at low concentrations. Coomassie Brilliant Blue G-250 (CBBG) concentration-dependent SERS spectra of CBBG–BSA and CBBG–antigen complexes at very low concentrations reveal a linear relationship of SERS intensities of CBBG in CBBG–BSA and CBBG–antigen complexes with respect to different BSA, HBV-cAg, and HCV-cAg concentrations could be clearly found. The as-designed SR-nAu samples are highly proficient in recognizing the protein biomarkers of highly similar chemical structures and can be used for determining the quantity of protein at low concentrations. The SR-nAu substrate is therefore promising for a rapid, high-sensitivity, and high-throughput diagnosis on proteins.