SERS-based multiple biomarker detection using a gold-patterned microarray chip

We report a highly sensitive surface-enhanced Raman scattering (SERS)-based immunoassay platform for the multiplex detection of biomarkers. For this purpose, a gold-patterned microarray chip has been fabricated and used as a SERS detection template. Here, a typical sandwich immunocomplex protocol was adopted. Monoclonal antibodies were immobilized on gold patterned substrates, and then antigen solutions and polyclonal antibody-conjugated hollow gold nanospheres (HGNs) were sequentially added for the formation of sandwich immunocomplexes. Antigen biomarkers can be quantitatively assayed by monitoring the intensity change of a characteristic SERS peak of a reporter molecule adsorbed on the surfaces of HGNs. Under optimized assay conditions, the limits of detections (LODs) were determined to be 10 fg/mL for human IgG and 10–100 fg/mL for rabbit IgG. In addition, the SERS-based immunoassay technique can be applied in a wider dynamic concentration range with a good sensitivity compared to ELISA. The proposed method fulfills the current needs of high sensitivity and selectivity which are essential for the clinical diagnosis of a disease.