Biogenic Silver Nanoparticles as an Antibiofouling (Bactericidal), Cytotoxic And Anticancereous Agents

Abstract

Nanotechnology is an emerging field of research with numerous roles in science and technology. It is used specifically for designing new agents and development of nanoparticles (NPs) with unique characteristics and broad-spectrum antibacterial activities. Nano-materials have diversified improved chemical composition and properties exhibiting a wide range of applications like agriculture, food processing and healthcare techniques. Nanotechnology is the fabrication of materials and devices under a 100 nm length scale. It is interrelated with the principle of chemistry, physics and engineering, which involves the processing, manufacturing and their applications at the nanometer scale. Currently, nanoparticles are gaining interest to address antibiotic resistance-related concerns as they can be used as a better alternative antimicrobial agent. Conventional antibiotics have been failed to treat infectious diseases due to the emergence of multidrug resistance (MDR) in some common pathogens. The current study aimed to formulate new antimicrobials from greener sources. In the midst of these efforts, nanotechnology is a newly emerged field, in which the synthesis of new nanoparticles through novel and efficient means is on the rise. The current work has been carried out to assess the potential of bacterial and plant species in the biosynthesis of silver nanoparticles. Cell-free culture supernatant of Bacteria i-e P. aeruginosa and leaf extracts of plants including Fraxinus xanthoxyloides (FX) and Bischofia j avanica (BJ) were used for biosynthesis of silver nanoparticles. This method is an economical and simple one-step approach to synthesize AgNPs. Characterization of Biogenic Silver nanoparticles (B-AgNPs) has been done by UV–Visible spectroscopy, X-ray diffraction (XRD), transmission electronic microscope (TEM) and Fourier transform Infrared spectroscopy (FT–IR).The formation of silver nanoparticles by P. ae ruginosa (PA-AgNPs) and FX–AgNPs has confirmed through UV–Visible spectroscopy (at 430 nm and For BJ-AgNPs at 422nm) by change of colour owing to surface Plasmon resonance. Based on the XRD pattern, the crystalline property of B-AgNPs has established. Functional groups existing in F. xanthoxyloides, B. javanica leaf extract and Cell-free supernatant of P. aeruginosa is confirmed by FT-IR spectrum. TEM authenticated morphology of the xviii AgNPs. Comparatively Silver nanoparticles synthesized from F. xanthoxyloides were better in terms of nm as compared to Silver nanoparticles synthesized from B. javanica which have an average size of 10±2.5 nm while Silver nanoparticles synthesized from P. aeruginosa (PA-AgNPs) have an average size of 20±9nm. The newly synthesized nanoparticles were evaluated for their antimicrobial potential. Minimum inhibitory concentration was determined against Escherichia co li, Methicillin-resistant Staphylococcus aur eus (MRSA) strains, Pseudomonas ae ruginosa, Candida al bicans an d K . pneumoniae by microtiter plate assay and well diffusion method. The lowest inhibition (69%) observed against MRSA was at a concentration of 50 ppm FX-AgNPs and maximum inhibition (81%) observed was against P .aeruginosa. For PA-AgNPs highest susceptibility was observed in the case of K. pnemoniae which exhibited a zone of inhibition 15mm against 300 and 400 ppm concentration. For BJ-AgNPs, the minimum zone of inhibition (6mm), was recorded for 100ppm of C. albicans for the highest concentration of K. pneumoniae (300ppm) 13mm zone of inhibition was recorded. Gram negative bacteria were more susceptible toward AgNPs as compared to Gram-positive bacteria. Synergistic behaviour of AgNPs + Ciprofloxacin and AgNPs + Ampicillin were also observed. The biosynthesized AgNPs triggered an 86.6% drop in the biofilm formation of P. aeruginosa as compared to the control, while chemically synthesized nanoparticles (C-AgNPs) showed a 70.87 drop. Metabolic activity of P. aeruginosa was investigated by XTT assay, Cells exposed to nanoparticles produced fewer amounts of reductase enzyme and displayed compromised metabolic activity by 62%. The hemolysis test measures the lysis of the red blood cells when exposed to an environmental agent. As the results indicate lysis was dose-dependent but still far less as compared to control. The PsF membranes were fabricated with different concentration of silver and utilized for the anti-biofouling study. Membranes were characterized by the FTIR, and SEM. At the concentration of 1.66 weights % highest reduction is observed against all the MDR strains. Membrane effectiveness for the long run was observed under the two conditions i.e. shaking and static under the time period of 7, 14 and 21 days. Overall results showed that the silver nanoparticles impregnated Psf membrane did not allow dense growth of biofilm as compared to Plain Psf membrane. The biogenic silver nanoparticles exhibit xix exceptional anticancer activity against the HeLa cell line and showed a reduction in cellular proliferation at 25 µM, further increase in concentration proved cytotoxic. In another study, we have developed hydrogels their antimicrobial and wound healing potential was evaluated through in-vivo studies. Silver nanoparticles coated hydrogel showed effective bactericidal activity against gram negative and gram positive bacteria, In rat models it could be clearly observed that chitosan has enhanced the wound healing and eliminated the risk of skin contraction or scar formation after healing, which could be clearly seen in control or sham group. Furthermore silver nanoparticles loaded hydrogels completely eliminated the bacterial infection in infected group and reduces the risk of sepsis leading to death which is the major issue in septic wounds. This study imparts a useful insight into the development of a new antimicrobial agent from a novel source