Comparative analysis of polydopamine and casein coated Arabic gum stabilized silver nanoparticles for enhanced antimicrobial activity of quercitrin

This study focuses on the green synthesis of silver nanoparticle (Ag NPs) stabilized by gum Arabic as a nano -carrier for quercitrin which was subsequently modified with casein (Cs) and polydopamine (PDA) to improve its antimicrobial potential against S. aureus. The developed gum Arabic based AgNPs (GA-Ag NPs) exhibited 67.31 +/- 0.01% encapsulation efficiency for quercitrin. Furthermore, the synthesized AgNPs were characterized using various techniques including UV-visible spectroscopy, Dynamic light scattering (DLS), FT-IR (Fourier transform infrared spectroscopy), and AFM (Atomic force microscopy). Finally, antibacterial activity of synthesized AgNPs was investigated against resistant and sensitive S. aureus strains. Results demonstrated the spherical shape morphology and nano range particle size for Cs and PDA modified quercetrin loaded GA-Ag NPs. Both the systems exhibited sustain drug release profile with maximum release of more than 70%. Furthermore, anti-bacterial study revealed that the MIC and MBIC of quercetrin significantly decreased after being functionalized with Cs and PDA. Results were further confirmed by analyzing the morphological changes in the bacterial cells utilizing AFM. However, the results were more obvious for PDA functionalized quercetrin loaded GA-AgNPs upon comparison with Cs modified system. Hence, the developed PDA functionalized NPs can serve as efficient delivery vehicles over the existing systems for increasing the bactericidal potentials of quercitrin.