Design, synthesis and optimization of silver nanoparticles using Azadirachta indica bark extract and its antibacterial application

Abstract

The upsurge of emerging infectious diseases over the past few years especially from bacteria is a major global threat. The antibiotic used for the treatment purposes has adverse health effects. Hence, there is a need for novel natural alternates to overcome such issues. In this research work, the antibacterial effects of bio-inspired silver nanoparticles from Azadirachta indica bark were explored. Herein, the AgNPs were synthesized using aqueous extract of A. indica bark. The optimization of parameters was carried out using Box-Behnken Design ver. 12. Using response surface methodology the conditions for biosynthesis of small sized and uniformly distributed nanoparticles were optimized. The physicochemical characterizations of AgNPs were done by DLS, SEM, Zeta potential and FTIR. The DLS and SEM data revealed the average size of particles to be 76.35 nm and 30.6 nm respectively. FTIR analysis has shown the involvement of conjugated alkenes in the biosynthesis and capping process. In this research, the biological applications of AIB-AgNPs were also explored. The antimicrobial activities were determined by disc diffusion, Congo red agar and Crystal violet assays. The antimicrobial activity was found to be increased in a dose dependent manner. We have also looked into the mechanistic aspect of antibacterial activity. For this, cellular damages caused by AgNPs treatment were studied by membrane leakage analysis. The binding of AgNPs with bacterial cell and cellular leakage were visualized by SEM. Lastly, changes in the functional groups of membrane composition of bacterial cells were depicted by FTIR.

Design, Synthesis, and Optimization of Silver Nanoparticles Using anArtocarpus heterophyllusLam. Leaf Extract and Its Antibacterial Application

“…3). The banding pattern of the functional group and the fingerprint region were similar to those of polyphenols specified by Chen and Mu [74] and Chavan et al [44]. The bands at 3 266.82 and 3 296.70 cm −1 , corresponding to O−H stretching Based on the FT-IR investigation, it can be assumed that phenolic and flavonoid compounds present in the AHAgNPs may be involved in capping and stabilizing the nanoparticles [75].…”

“…A crude extract of AHL was used for the synthesis of AHAgNPs, and silver nitrate was the source of silver according to the method described by Refs. [43,44] with slight modifications. Furthermore, the most important parameters, like the concentrations of AgNO 3 (μg/mL) and the extract (μg/mL), were optimized by Design Expert Ver.…”

“…The scavenging capacity of natural plant antioxidants and nanoparticles against the stable DPPH free radicals was measured by Chavan et al [44] and Mensor et al [49]. Mathur et al [50] and Irshad [51] slightly modified.…”