Glucose detection using 4-mercaptophenyl boronic acid-incorporated silver nanoparticles-embedded silica-coated graphene oxide as a SERS substrate

In this work, 4-mercaptophenyl boronic acid (4-MPBA) was self-assembled on the surface of silver nanoparticle-embedded silica-coated graphene oxide (GO@SiO₂@Ag NPs@MPBA) to detect glucose by surface enhanced Raman scattering (SERS). The SERS intensity of 4-MPBA on the GO@SiO₂@Ag NPs was 2.2-fold greater than that of GO@Ag NPs. Moreover, silica-coated GO exhibited lower background signals compared to GO. The SERS intensity of GO@SiO₂@Ag NPs@MPBA peaked at 1 mM 4-MPBA. pH-dependent behavior of 4-MPBA on the GO@SiO₂ @Ag NPs was investigated; the highest SERS signal intensity was detected at pH 3. The binding of glucose to 4-MPBA-incorporated GO@SiO₂@Ag NPs increased the SERS signals at both 1,072 and 1,588 cm^-1. The linear range was estimated from 2 to 20 mM glucose. These results provide insight into detection of glucose and the development of SERS-based biosensors using graphene oxide.