A facile and sensitive glucose sandwich assay using surface-enhanced Raman scattering (SERS) has been developed through the use of the self-assembled p-mercaptophenylboronic acid (PMBA) monolayer on a smooth gold-coated slide and the SERS tags of Ag nanoparticles (AgNPs) modified with p-aminothiophenol (PATP) and PMBA. The photocoupling product 4,4'-dimercaptoazobenzene (DMAB), generated in situ from PATP on the AgNP surface during the SERS measurement, possessed considerably intense characteristic SERS peaks and acted as the actual Raman reporter, which improved the sensitivity of glucose detection devoid of interference of other biomolecules. The facile sandwich assay showed a high selectivity of glucose over fructose and galactose. This facile, sensitive, and selective SERS-based glucose sandwich assay can be developed into a diagnostic tool for determination of glucose levels.

Sensitive surface-enhanced Raman scattering (SERS) assays of glycoproteins have been proposed using p-aminothiophenol (PATP)-embedded Ag core-Au satellite nanostructures modified with p-mercaptophenylboronic acid (PMBA) and the self-assembled monolayer of PMBA on a smooth gold-coated wafer. The apparent Raman probe PATP on the surfaces of the Ag cores underwent a photodimerization to generate 4,4'-dimercaptoazobenzene (DMAB) in situ upon excitation of laser, and the in situ generated DMAB acted as the actual Raman probe with considerably strong SERS signals, which was further enhanced by the plasmonic coupling of the Ag core-Au satellite nanostructures due to the synergistic effect. The sandwich assays of glycoproteins showed high sensitivity and excellent selectivity against nonglycoproteins. The Ag core-Au satellite SERS nanostructures can be used for highly sensitive SERS assays of other analytes.