Aloe vera leaf extract-mediated green synthesis of silver nanoparticles: physicochemical characterization and evaluation for multifaceted applications

Abstract Silver nanoparticles were synthesized using the extract of Aloe vera leaves and the presence of light enhanced the synthesis of phytogenic silver nanoparticles. The colour change from opaque white to brown is the initial indication for the synthesis of silver nanoparticles, that was further confirmed by UV-Vis spectroscopy exhibiting λ max at 440 nm. The highest synthesis of AgNPs was recorded at 50 °C. Atomic force microscopy confirmed the average size of silver nanoparticles as ˂100 nm and zeta potential as 77.4 nm with a surface charge of -21.4 mV. X-ray diffraction analysis showed crystalline nature of phytogenic silver nanoparticles. Green nanoparticles showed antimicrobial activity against bacteria ( Escherichia coli DH5α and Bacillus subtilis subsp. subtilis JJBS250) and a thermophilic mould, Myceliophthora thermophila BJAMDU7 with a minimum inhibitory concentration of approximately 100 µg/ml. Phytogenic silver nanoparticles did not show hemolysis and cytotoxicity activity. Further, green nanoparticles inhibited the growth of Plasmodium falciparum showing antimalarial potential. Malachite green and gentian violet were decolorized 82% and 72%, respectively after 48 h by these nanoparticles. Green synthesized nanoparticles also showed catalytic reduction of p -nitrophenol. Aloe vera ’s ability in green silver nanoparticles synthesis showed potential for clinical therapies and environmental remediation.