Synergistic effect of boric acid affinity magnetic materials and multi-hotspot SERS substrates for high sensitivity detection of glucose

Abstract

In this work, boric acid affinity magnetic materials and Au nanorods capped by an Ag (AuNRs@Ag) core–shell structure were used to construct the sandwich structure to obtain a surface-enhanced Raman spectroscopy (SERS) sensor for detecting glucose. AuNRs@Ag was modified with 4-mercaptophenylboronic acid (4-MPBA) as the SERS substrate, illustrating the efficient electromagnetic enhancement. Moreover, the boric acid affinity magnetic materials (FMNPs) were further functionalized with knife bean lectin as a “capture probe”, which illustrated the high adsorption capacity for glucose. The maximum adsorption amount can reach 33.3 mg g⁻¹. The conditions for preparing the SERS platform as well as glucose detection were optimized. Under the optimal experimental conditions, the detection linear range for glucose is 1.0 × 10⁻¹¹ to 1.0 × 10⁻³ mol L⁻¹ with a limit of detection (LOD) of 1.8 × 10⁻¹² mol L⁻¹ (S/N = 3). In addition, the developed SERS sensor was further applied for the determination of glucose in human urine with recoveries in the range of 97.5% to 101.5%. As expected, the prepared sandwich SERS sensor was successfully employed to recognize and detect glucose with high sensitivity.