title: Bio-fabricated silver nanoparticles preferentially targets Gram positive depending on cell surface charge.
abstract: Recently bio-inspired experimental processes for synthesis of nanoparticles are receiving significant attention in nanobiotechnology. Silver nanoparticles (Ag NPs) have been used very frequently in recent times to the wounds, burns and bacterial infections caused by drug-resistant microorganisms. Though, the antibacterial effects of Ag NPs on some multi drug-resistant bacteria specially against Gram positive bacteria has been established, but further investigation is needed to elicit its effectiveness against Gram negatives and to identify the probable mechanism of action. Thus, the present study was conducted to synthesize Ag NPs using Andrographis paniculata leaf extract and to investigate its antibacterial efficacy. After synthesis process the biosynthesized nanoparticles were purified and characterized with the help of various physical measurement techniques which raveled their purity, stability and small size range. The antimicrobial activity of Ag NPs was determined against both Gram-positive Enterococcus faecalis and Gram-negative Proteus vulgaris. Results showed comparatively higher antibacterial efficacy of Ag NPs against Gram positive Enterococcus faecalis strains. It was found that greater difference in zeta potential values between Gram positive bacteria and Ag NPs triggers better internalization of the particles. Thus the cell surface charge played vital role in cell killing which was confirmed by surface zeta potential study. Finally it may be concluded that green synthesized Ag NPs using Andrographis paniculata leaf extract can be very useful against both multi drug resistant Gram-positive and Gram-negative bacteria.
authors.affiliation: Immunology and Microbiology Laboratory, Department of Human Physiology with Community Health, Vidyasagar University, Midnapore-721 102, West Bengal, India.
authors.forename: Debasis
authors.initials: D
authors.lastname: Mandal
authors.affiliation: Immunology and Microbiology Laboratory, Department of Human Physiology with Community Health, Vidyasagar University, Midnapore-721 102, West Bengal, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kumar Dash
authors.affiliation: Immunology and Microbiology Laboratory, Department of Human Physiology with Community Health, Vidyasagar University, Midnapore-721 102, West Bengal, India.
authors.forename: Balaram
authors.initials: B
authors.lastname: Das
authors.affiliation: Immunology and Microbiology Laboratory, Department of Human Physiology with Community Health, Vidyasagar University, Midnapore-721 102, West Bengal, India.
authors.forename: Sourav
authors.initials: S
authors.lastname: Chattopadhyay
authors.affiliation: Department of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel.
authors.forename: Totan
authors.initials: T
authors.lastname: Ghosh
authors.affiliation: Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700 009, India.
authors.forename: Debasis
authors.initials: D
authors.lastname: Das
authors.affiliation: Immunology and Microbiology Laboratory, Department of Human Physiology with Community Health, Vidyasagar University, Midnapore-721 102, West Bengal, India. Electronic address: sroy.vu@hotmail.com.
authors.forename: Somenath
authors.initials: S
authors.lastname: Roy
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001672:Biocompatible Materials / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002462:Cell Membrane / Q000737:chemistry* / Q000187:drug effects; D004058:Diffusion; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D000067493:Dynamic Light Scattering; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000648:ultrastructure; D057446:Hydrodynamics; D007477:Ions; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000378:metabolism; D012834:Silver / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D007477:Ions; D017382:Reactive Oxygen Species; D012834:Silver
keywords: Andrographis paniculata; Antibacterial activity; Green synthesis; Silver nanoparticles; Zeta potential