Gold nanoparticles synthesized from Bacopa monneri plant extract: Bovine serum albumin protein interactions and antibacterial effectiveness

Gold nanoparticles (AuNPs) are widely used in various scientific and technological domains, particularly biomedicine due to their superior biocompatibility. This study focuses on the synthesis of biogenic gold nanoparticles (B-Au) and chemogenic gold nanoparticles (C-Au) and their interactions with bovine serum albumin (BSA) proteins. BSA is a crucial protein in physiological processes and serves as an ideal model for biofunctionalization studies. The techniques like fluorescence and UV–visible spectroscopy were used to investigate the binding interactions between BSA and AuNPs. Field-emission electron microscopy (FESEM) was used to determine the size and shape of biogenic AuNPs, while zeta potential measurements were used to detect surface charge and predict stability. According to dynamic light sacttering measurements, the sizes of C-Au and B-Au are 71 and 83 nm, respectively. A single B-Au is surrounded by 1124 protein molecules, whereas a single C-Au has 672 BSA molecules attached to it. This implies that the biogenic B-Au's greater size and multifunctional groups on its surface allow it to retain more protein. BSA effectively interacts with both C-Au and B-Au, as confirmed by the spectrum features that support the stable association supported by both covalent and electrostatic interactions, as determined by Fourier transform infrared spectroscopy analysis.Comparing the B-Au-BSA and C-Au-BSA protein complexes to unmodified nanoparticles, the results demonstrated increased stability. The inhibitory zones for B-Au-BSA and C-Au-BSA were 8 mm and 7 mm, respectively, at a dosage of 6 µM. Functionalizing AuNPs with BSA increased their antibacterial efficacy, making them a viable substitute for chemical disinfectants and traditional antibiotics.