RESUMEN
The present study aimed to synthesise bio-molecule functionalized silver nanoparticles (AgNPs) using leaf extract from mulberry variety S-1635 (Morus alba L.) and to explore its antibacterial efficacy against multidrug resistant (MDR) gut bacteria isolated from natural infection observed from silkworm larvae in rearing conditions. AgNPs formation was established by surface plasmon resonance at 480 nm. The crystallinity of the synthesised AgNPs was checked by HR-TEM and XRD analysis. SEM and TEM characterisation further exhibited the spherical, monodispersed, well scattered nature of the AgNPs with an average particle size of 11.8 nm ± 2.8. The presence of (111), (200), (220) and (311) planes in Bragg's reflections confirmed the face-cantered-cubic crystalline silver. EDX analysis confirmed the presence of elemental silver. FT-IR spectra revealed functional groups were responsible for the reduction of silver ions. The zeta potential value of -17.3 mV and -25.6 mV was recorded in MH and DMEM/F-12 media, respectively. The LC-QTOF/MS and HRMS spectra disclosed the presence of bioactive compounds like flavonoid, gallic acid, and stigmasterol, which are probably involved in the reduction and functionalization of AgNPs. The antibacterial efficacy of bio-molecule functionalized AgNPs and the naked AgNPs was tested on Gram-positive and Gram-negative bacteria isolated from silkworms and characterized by using 16S rDNA and gyrB genes. The cytotoxicity of AgNPs was tested on WRL-68, HEK-293, ACHN, and HUH-7 cell lines using MTT assay. This study provides an insight into the application of bio-molecule functionalized AgNPs for combating various silkworm pathogens which severely affect the agro-rural economy of developing countries.
RESUMEN
Core-shell α-Fe2O3-ZnO structures of different nanotextured morphology were synthesized through wet chemical routes using different solvents like ethanol, ethanolamine, water and acetaldehyde. Morphological tuning using different solvents resulted in the formation of different shapes, such as disc, spindle, rod and sphere (abbreviated as FZ-ND, FZ-NSP, FZ-NR and FZ-NS, respectively). Structural, morphological and compositional characterization of these nanoparticles (NPs) has been carried out. Antibacterial efficacy of the synthesized NPs was checked against Gram negative V. cholerae N16961 (VcN16961) and Gram positive S. aureus bacteria by recording optical density (OD) at different time points. Among the NPs tested, FZ-NSP was found to be the most effective against VcN16961, while FZ-NR showed maximum efficacy against S. aureus, implying the importance of nanotextured surface as well as the morphology in the manifestation of antibacterial activity. The kinetics of growth for both the bacteria has been modelled using logistic approach. Cytotoxicity was evaluated through MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide) assay against human breast adenocarcinoma cell line (MCF-7), human hepatocarcinoma cell line (HepG2) and against normal human embryonic kidney cell line (HEK-293). The lesser toxicity of α-Fe2O3-ZnO towards HEK-293 and the potent anticancer activity against MCF-7 and HepG2 cells underline its applicability as anticancer agent. With continued improvement of nanotechnology, this study may pave the way for designing and construction of various morphologically diverse, nanotextured materials with desired functional attributes.
