Silver nanoclusters stabilized with PVP-BSA conjugate: Optical properties approach

The objective of this research was to synthesize fluorescent silver nanoclusters (NC Ag-BSA/PVP) using polyvinylpyrrolidone polymer (PVP) as a stabilizer in conjunction with bovine serum albumin protein (BSA). The nanoclusters were prepared using a wet chemistry reduction technique with two distinctive pathways: the addition of PVP after BSA and the addition of PVP after the metal precursor. The optical properties of the materials were studied in samples with different BSA/PVP molar ratios and varying amounts of metal/reductant. The impact of protein and polymer amounts on fluorescence was determined. The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray energy dispersive spectroscopy (EDS), dynamic light scattering (DLS), fluorescence spectroscopy, and UV-Vis-NIR spectroscopy.

It was observed that increasing the BSA/PVP ratio resulted in higher fluorescence intensity at λ = 450 nm and a decrease at λ = 600 nm. Regarding the metal/reductant ratio, the amount of metal ions impacted the intensity obtained at λ = 600 nm. The experiments revealed that BSA had the largest effect on fluorescence intensity at λ = 450 nm, with little effect on fluorescence intensity regardless of the amount of polymer used. Due to its one-step synthesis and favorable reaction conditions, the NC Ag-BSA/PVP obtained under the proposed methodology holds promise as an optical marker material. The use of the stabilizing duo BSA-PVP, as well as the proposed amounts in this research, serves as a precedent for developing new experimental syntheses of colloidal nanoparticles.