Boronic acid functionalized quantum dots/AuNPs and metal enhanced fluorescence for selective glucose detection

The development of effective glucose monitoring methods is essential for diabetic patients, enabling them to better manage their blood glucose levels and prevent severe complications such as myocardial infarction and renal failure. In this study, we successfully constructed a fluorescent probe based on aminobenzeneboronic acid functionalized CdTe quantum dots (QDs-APBA) and mercaptophenylboronic acid modified gold nanoparticles (MPBA-AuNPs). The fluorescence intensity of QDs-APBA was influenced by the metal enhanced fluorescence (MEF) effect from MPBA-AuNPs, achieving a 2.6-fold enhancement. The fluorescence lifetime demonstrated that the mechanism of MEF was localized surface plasmon resonance (LSPR) instead of intrinsic radiative decay rate effect. Meanwhile, the influences of AuNPs size on the local electric field were analyzed in detail using the Finite-Difference Time-Domain (FDTD) method. These findings were in good agreement with the experimental results. Finally, the assembly has further been applied to glucose detection. Under pH 7.4 conditions, the assembly probe exhibited excellent selectivity and sensitivity for glucose detection with a detection limit of 2.8 μM and a linear range of 3.3-150 μM. This probe allowed for visual detection of glucose concentration changes with the naked eye. Specifically, we detected glucose using alginate hydrogel microspheres embedded with QDs-APBA and MPBA-AuNPs (QD-AuNP MS) and showed the reversible interaction between phenylboronic acid and glucose. This innovative approach not only improves the selectivity and sensitivity of glucose detection but also offers a new strategy for the development of advanced glucose-detecting technologies.