title: The effects of bacteria-nanoparticles interface on the antibacterial activity of green synthesized silver nanoparticles.
abstract: Neutralization of bacterial cell surface potential using nanoscale materials is an effective strategy to alter membrane permeability, cytoplasmic leakage, and ultimate cell death. In the present study, an attempt was made to prepare biogenic silver nanoparticles using biomolecules from the aqueous rhizome extract of Coptis Chinensis. The biosynthesized silver nanoparticles were surface modified with chitosan biopolymer. The prepared silver nanoparticles and chitosan modified silver nanoparticles were cubic crystalline structures (XRD) with an average particle size of 15 and 20 nm respectively (TEM, DLS). The biosynthesized silver nanoparticles were surface stabilized by polyphenolic compounds (FTIR). Coptis Chinensis mediated silver nanoparticles displayed significant activity against E. coli and Bacillus subtilus with a zone of inhibition 12 ± 1.2 (MIC = 25 μg/mL) and 18 ± 1.6 mm (MIC = 12.50 μg/mL) respectively. The bactericidal efficacy of these nanoparticles was considerably increased upon surface modification with chitosan biopolymer. The chitosan modified biogenic silver nanoparticles exhibited promising activity against E. coli (MIC = 6.25 μg/mL) and Bacillus subtilus (MIC = 12.50 μg/mL). Our results indicated that the chitosan modified silver nanoparticles were promising agents in damaging bacterial membrane potential and induction of high level of intracellular reactive oxygen species (ROS). In addition, these nanoparticles were observed to induce the release of the high level of cytoplasmic materials especially protein and nucleic acids into the media. All these findings suggest that the chitosan functionalized silver nanoparticles are efficient agents in disrupting bacterial membrane and induction of ROS leading to cytoplasmic leakage and cell death. These findings further conclude that the bacterial-nanoparticles surface potential modulation is an effective strategy in enhancing the antibacterial potency of silver nanoparticles.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China. Electronic address: aftabbiochem@yahoo.com.
authors.forename: Aftab
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Institute of Chemical Sciences, University of Peshawar, 25120 Peshawar, Pakistan.
authors.forename: Fatima
authors.initials: F
authors.lastname: Syed
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China.
authors.forename: Kamran
authors.initials: K
authors.lastname: Tahir
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China.
authors.forename: Aziz Ur
authors.initials: AU
authors.lastname: Rehman
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China.
authors.forename: Arifullah
authors.initials: A
authors.lastname: Khan
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China.
authors.forename: Sadeeq
authors.initials: S
authors.lastname: Ullah
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, No. 15 East Road of North Third Ring, Chao Yang District, Beijing 100029, China. Electronic address: yuanqp@mail.buct.edu.cn.
authors.forename: Qipeng
authors.initials: Q
authors.lastname: Yuan
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D055772:Green Chemistry Technology; D008564:Membrane Potentials / Q000187:drug effects; D053768:Metal Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D010316:Particle Size; D056951:Photoelectron Spectroscopy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D012834:Silver / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D012834:Silver
keywords: Bacteria; Coptis Chinensis; Membrane potential; Silver nanoparticles