title: Enhanced Photothermal Bactericidal Activity of the Reduced Graphene Oxide Modified by Cationic Water-Soluble Conjugated Polymer.
abstract: Surface modification of graphene is extremely important for applications. Here, we report a grafting-through method for grafting water-soluble polythiophenes onto reduced graphene oxide (RGO) sheets. As a result of tailoring of the side chains of the polythiophenes, the modified RGO sheets, that is, RGO-g-P3TOPA and RGO-g-P3TOPS, are positively and negatively charged, respectively. The grafted water-soluble polythiophenes provide the modified RGO sheets with good dispersibility in water and high photothermal conversion efficiencies (ca. 88%). Notably, the positively charged RGO-g-P3TOPA exhibits unprecedentedly excellent photothermal bactericidal activity, because the electrostatic attractions between RGO-g-P3TOPA and Escherichia coli (E. coli) bind them together, facilitating direct heat conduction through their interfaces: the minimum concentration of RGO-g-P3TOPA that kills 100% of E. coli is 2.5 μg mL-1, which is only 1/16th of that required for RGO-g-P3TOPS to exhibit a similar bactericidal activity. The direct heat conduction mechanism is supported by zeta-potential measurements and photothermal heating tests, in which the achieved temperature of the RGO-g-P3TOPA suspension (2.5 μg mL-1, 32 °C) that kills 100% of E. coli is found to be much lower than the thermoablation threshold of bacteria. Therefore, this research demonstrates a novel and superior method that combines photothermal heating effect and electrostatic attractions to efficiently kill bacteria.
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , 29 Zhongguancun East Road, Haidian District, Beijing 100190, China.|University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, China.
authors.forename: Linhong
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , 29 Zhongguancun East Road, Haidian District, Beijing 100190, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Sun
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Libing
authors.initials: L
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Hu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Lu
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , 29 Zhongguancun East Road, Haidian District, Beijing 100190, China.
authors.forename: Chungui
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , 29 Zhongguancun East Road, Haidian District, Beijing 100190, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Shu
authors.identifier: http://orcid.org/0000-0001-8781-2535
authors.initials: S
authors.lastname: Wang
authors.affiliation: Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , 29 Zhongguancun East Road, Haidian District, Beijing 100190, China.
authors.forename: Jianxin
authors.identifier: http://orcid.org/0000-0003-0428-4621
authors.initials: J
authors.lastname: Geng
mesh_terms: D004926:Escherichia coli; D006108:Graphite / Q000737:chemistry*; D010087:Oxides; D011108:Polymers; D014867:Water
chemical_list: D010087:Oxides; D011108:Polymers; C000628730:graphene oxide; D014867:Water; D006108:Graphite
keywords: covalent functionalization; electrostatic attraction; graphene; photothermal killing of bacteria; water-soluble conjugated polymers