Biosynthesis of CdS nanoparticles and their stabilization by fungal biomolecules
摘要
Several methods for synthesizing stable cadmium sulfide nanoparticles (CdS NPs) using fungus for reduction and coating have been studied; however, the metabolites involved have been scarcely studied. The aim of the present study was to characterize the biomolecules obtained using methanol from the biomass of Fusarium oxysporum f.sp. lycopersici and to evaluate their role as reducing and stabilizing agents in CdS nanoparticle synthesis. The reducing power of the fungal biomass methanolic supernatant was assessed by FRAP and ABTS, along with NADH, protein and sulfhydryl (–SH) groups content, and a metabolomic profile by UPLC-MS. CdS NPs characterization included fluorescence and UV–VIS spectroscopy, FTIR, zeta potential as a function of pH, TEM and EDS, and DLS. Analyses of the supernatant showed 1104.1 ± 0.86 µmol Fe2+/mL of FRAP, 29.6% of ABTS reduction complex, 0.51 ± 0.03 mmol/L NADH, 0.24 ± 0.004 mg/mL of proteins and 130.35 ± 7.58 µmol/L of –SH groups. Metabolomic profile revealed secondary metabolites within 136 to 600 Da. FTIR results evidenced the presence of vibrations corresponding to Cd-S bonds at 779 and 585 cm−1. Spectroscopy analysis of NPs showed their resonance plasmon absorption at 320 nm and the emission peak at 515 nm. The synthesis of CdS NPs was performed with an average size of 1.73 ± 0.77 nm in a stable colloidal solution with a zeta potential value of − 28.1 mV at pH 8.78. DLS analysis showed an average hydrodynamic diameter of 147.7 nm with a PDI of 0.061, indicating a narrow size distribution in colloidal solution . Results strongly suggest the effect of zeta potential of the colloidal nanoparticle solution by both the electrical charges and functional groups of the biomolecules at pH 8.78.