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The present study reported a single step synthesis of silver nanoparticles using ampicillin (Amp-AgNps), a second-generation β lactam antibiotic to get nanoformulation having dual properties that of antibiotic and silver. The Amp-AgNps was characterized by UV-VIS spectroscopy, TEM, XRD, FTIR and TGA. FTIR and TGA results suggested that amine group of Ampicllin reduce the metalic silver into nano form. These results were further validated by computational molecular dynamics simulation. The antibacterial potential of Amp-AgNps was investigated against sensitive and drug resistant bacteria. MIC of Amp-AgNps against 6 different bacterial strains were in the range of 3–28 µg/ml which is much lower than the MIC of ampicillin (12–720 µg/ml) and chemically synthesized silver nanoparticles (280–640 µg/ml). The repeated exposure to drugs may lead to development of resistance mechanism in bacteria against that drug, so the efficacy of Amp-AgNps after repeated exposure to bacterial strains were also studied. The results indicate that bacterial strains do not show any resistance to these Amp-AgNps even after exposure up to 15 successive cycles. The biocompatibility of these Amp-AgNps was checked against cell lines by using Keratinocytes cell lines (HaCaT).

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Alcoholic extract of tulsi leaves was used as a reducing and stabilizing agent for the synthesis of silver nanoparticles (AgNPs). The use of plant extract for the synthesis of nanoparticles is cost-effective, single step, and an ecofriendly process. The biosynthesized AgNPs were characterized using UV-Vis, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The AgNPs formed show surface plasmon resonance at 430 nm. They have a smooth surface with an average diameter of 2-7 nm. Their crystalline nature was confirmed by the XRD. The antifungal activity of the AgNPs was evaluated for opportunistic human fungal pathogens Candida albicans, Candida glabrata, and Candida tropicalis. The antifungal effect was determined by minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and disk diffusion assay. Further, to assess the pathogenicity, proteinase and phospholipase assays were performed. TEM analysis of treated Candida cells reveals that the AgNPs may be exerting antifungal activity by disrupting the cell membrane structure and integrity. Cytotoxicity of AgNPs was checked by performing hemolytic assay against human erythrocytes. At MIC values, AgNPs caused only 5.6 % lysis in RBCs which was very low in comparison to conventional antifungal agents. Hence, biosynthesized AgNPs using plant extracts have immense antifungal potential and can be used in the management of fungal infections. Further studies have to be done to understand their mode of action.

Lactoferrin is an 80 kDa bilobal, iron binding glycoprotein which is primarily antimicrobial in nature. The hydrolysis of lactoferrin by various proteases in the gut produces several functional fragments of lactoferrin which have varying molecular sizes and properties. Here, bovine lactoferrin has been hydrolyzed by trypsin, the major enzyme present in the gut, to produce three functional molecules of sizes approximately 21 kDa, 38 kDa and 45 kDa. The molecules have been purified using ion exchange and gel filtration chromatography and identified using N-terminal sequencing, which reveals that while the 21 kDa molecule corresponds to the N2 domain (21LF), the 38 kDa represents the whole C-lobe (38LF) and the 45 kDa is a portion of N1 domain of N-lobe attached to the C-lobe (45LF). The iron binding and release properties of 21LF, 38LF and 45LF have been studied and compared. The sequence and structure analysis of the portions of the excision sites of LF from various species have been done. The antibacterial properties of these three molecules against bacterial strains, Streptococcus pyogenes, Escherichia coli, Yersinia enterocolitica and Listeria monocytogenes were investigated. The antifungal action of the molecules was also evaluated against Candida albicans. This is the first report on the antimicrobial actions of the trypsin cleaved functional molecules of lactoferrin from any species.