Development of a novel nanoprobe from alginate functionlized gold nanoparticles and 3-(dansylamino)phenylboronic acid for glucose detection and enhanced 4-nitrophenol reduction

Gold nanoparticles (AuNPs) were prepared by a solvothermal method using sodium alginate (SA) as both, the reductant and stabilizer. The formation of SA-AuNPs was confirmed by UV-Vis spectroscopy, transmission electron microscopy, X-ray diffractometry, and X-ray photoelectron spectroscopy. SA-AuNPs were functionalized with fluorescent 3-(dansylamino)phenylboronic acid (DAPB) moieties, through interactions between boronic acids and diol groups. The fluorescence resonance energy transfer from DAPB to AuNPs quenched the fluorescence of DAPB. In the presence of glucose, the competitive binding of DAPB with glucose resulted in the release of assembled DAPB from the surface of SA-AuNPs, resulting in the increase in fluorescence intensity. Furthermore, catalytic reduction of 4-nitrophenol was monitored via spectrophotometry using DAPB functionalized SA-AuNPs probes as catalyst. Compared to SA-AuNPs, the nanoprobes exhibited higher catalytic rates.