title: Synergism of Water Shock and a Biocompatible Block Copolymer Potentiates the Antibacterial Activity of Graphene Oxide.
abstract: Graphene oxide (GO) is promising in the fight against pathogenic bacteria. However, the antibacterial activity of pristine GO is relatively low and concern over human cytotoxicity further limits its potential. This study demonstrates a general approach to address both issues. The developed approach synergistically combines the water shock treatment (i.e., a sudden decrease in environmental salinity) and the use of a biocompatible block copolymer (Pluronic F-127) as a synergist co-agent. Hypoosmotic stress induced by water shock makes gram-negative pathogens more susceptible to GO. Pluronic forms highly stable nanoassemblies with GO (Pluronic-GO) that can populate around bacterial envelopes favoring the interactions between GO and bacteria. The antibacterial activity of GO at a low concentration (50 μg mL(-1) ) increases from <30% to virtually complete killing (>99%) when complemented with water shock and Pluronic (5 mg mL(-1) ) at ≈2-2.5 h of exposure. Results suggest that the enhanced dispersion of GO and the osmotic pressure generated on bacterial envelopes by polymers together potentiate GO. Pluronic also significantly suppresses the toxicity of GO toward human fibroblast cells. Fundamentally, the results highlight the crucial role of physicochemical milieu in the antibacterial activity of GO. The demonstrated strategy has potentials for daily-life bacterial disinfection applications, as hypotonic Pluronic-GO mixture is both safe and effective.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.|Singapore Institute of Manufacturing Technology (SIMTech), Singapore, 638075, Singapore.
authors.forename: H Enis
authors.initials: HE
authors.lastname: Karahan
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.
authors.forename: Li
authors.initials: L
authors.lastname: Wei
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.
authors.forename: Kunli
authors.initials: K
authors.lastname: Goh
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.
authors.forename: Christian
authors.initials: C
authors.lastname: Wiraja
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Liu
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.|NTU-Northwestern Institute of Nanomedicine, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
authors.forename: Chenjie
authors.initials: C
authors.lastname: Xu
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Singapore Institute of Manufacturing Technology (SIMTech), Singapore, 638075, Singapore.
authors.forename: Jun
authors.initials: J
authors.lastname: Wei
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.|School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, 2006, Australia.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001672:Biocompatible Materials / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000648:ultrastructure; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006108:Graphite / Q000494:pharmacology* / Q000633:toxicity; D006801:Humans; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D010316:Particle Size; D020442:Poloxamer / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D014867:Water / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D014867:Water; D020442:Poloxamer; D006108:Graphite
keywords: antibacterials; gram-negative; graphene oxide; hypoosmotic stress; pluronic