title: Systematic Study of Inherent Antibacterial Properties of Magnesium-based Biomaterials.
abstract: Magnesium-based materials are preferred in temporary orthopedic implants because of their biodegradability, mechanical properties, and intrinsic antibacterial properties. However, the fundamental mechanism of bacteria killing and roles of various factors are not clearly understood. In this study, we performed a systematic study of the antibacterial properties of two common Mg-based materials using a biofilm forming bacterium. Complete annihilation of the initial 3 × 10(4) bacteria is achieved with both materials in 0.1 mL LB medium in 24 h, whereas in the control, they proliferate to 10(10). The bacteria are killed more effectively in the solution than on the surface, and the bacteria killing efficiency depends more on the concentrations of the magnesium ions and hydroxyl ions than the corrosion rate. The killing process is reproduced using formula solutions, and killing is revealed to stem from the synergetic effects of alkalinity and magnesium ions instead of either one of them or Mg(OH)2 precipitate. Reactive oxygen species (ROS) are detected from the bacteria during the killing process but are not likely produced by the redox reaction directly, because they are detected at least 3 h after the reaction has commenced. The average cell size increases during the killing process, suggesting that the bacteria have difficulty with normal division which also contributes to the reduced bacteria population.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Hongqing
authors.initials: H
authors.lastname: Feng
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Guomin
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Jin
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Xuming
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Ang
authors.initials: A
authors.lastname: Gao
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Guosong
authors.initials: G
authors.lastname: Wu
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong China.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Chu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D001672:Biocompatible Materials / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003343:Corrosion; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008274:Magnesium / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D012996:Solutions; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D013499:Surface Properties
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D007477:Ions; D017382:Reactive Oxygen Species; D012996:Solutions; D008274:Magnesium
keywords: alkalinity; antibacterial properties; magnesium ion release; magnesium-based biomaterials; oxidative stress