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Abstract
The synthesis, characterization, and antimicrobial efficacy of biogenic aluminium-potassium hybrid nanoparticles (Pl-Al/KNPs) synthesized using Polyalthia longifolia leaf extract are presented. Aluminium chloride and potassium chloride were used as precursors, and the green synthesis approach leveraged the phytochemicals in P. longifolia for capping and stabilizing the nanoparticles. A significant colour change during the synthesis, attributed to Surface Plasmon Resonance (SPR), confirmed nanoparticle formation. Characterization using ATR-FTIR spectroscopy revealed the involvement of functional groups such as hydroxyl (-OH), carbonyl (-C=O), and phenolic (-C-OH) groups, which played crucial roles in reducing metal ions and stabilizing the nanoparticles. SEM micrographs indicated that the nanoparticles were predominantly spherical with sizes ranging from 70 to 103 nm. Slight agglomeration and non-uniform distribution were observed, likely due to the natural variability in phytochemical composition. EDX analysis confirmed the elemental composition of the nanoparticles, with aluminium (49.11%) and potassium (24.99%) as the primary constituents, along with trace elements like magnesium, silicon, and calcium, enhancing the stability and functionality of the nanoparticles. The antimicrobial efficacy of Pl-Al/KNPs was evaluated against multi-drug-resistant clinical isolates of Staphylococcus aureus, Salmonella spp., and Streptococcus spp. using the Kirby-Bauer disk diffusion method. Pl-Al/KNPs exhibited significant zones of inhibition: Staphylococcus aureus (18.5 mm), Salmonella spp. (16.8 mm), and Streptococcus spp. (17.3 mm), outperforming the zones observed with P. longifolia extract alone. These findings underscore the potential of Pl-Al/KNPs as eco-friendly antimicrobial agents, relevant for combating drug-resistant pathogens and advancing sustainable nanotechnology for healthcare applications.
