Linker-mode surface-enhanced Raman sensing of glucose via aromatic ring stretching in 3-Thienylboronic acid-Ag...

Surface enhanced Raman Scattering (SERS) platform based on Ag nanoclusters functionalized with 3-thienylboronic acid (3-TBA) is developed for glucose detection. Unlike conventional SERS glucose sensors that rely on the intrinsically weak Raman signatures of glucose, the present approach exploits the variability of an aromatic ring stretching mode of the linker molecule as a quantitative reporter. A distinct Raman band at ∼1589 cm^-1, assigned to the aromatic ring stretching vibration of 3-TBA, exhibits a linear intensity response to d-glucose concentration in the physiologically relevant range of 20-1000 μmolL^-1. Density functional theory calculations confirm the origin of this mode and elucidate its enhancement upon Ag binding and glucose-boronic acid interaction. The single-band, linker-mediated sensing strategy presented here simplifies signal acquisition while offering robustness and mechanistic clarity, providing a promising framework for portable and non-invasive glucose monitoring devices.