title: Effect of ZnO morphology on affecting bactericidal property of ultra high molecular weight polyethylene biocomposite.
abstract: Bacterial infection of implants can be controlled by selective trapping of bacteria, followed with consequent killing by targeted antibacterial agents. Herein, the role of various ZnO morphologies, viz. micro-rods (R), nanoparticles (NP), and micro-disks (D) on antibacterial efficacy of ZnO via release of Zn(2+) and H2O2 is assessed, both as isolated powders and via incorporating them in cytocompatible ultra high molecular weight polyethylene (UHMWPE). Though ZnO is antibacterial, interestingly, all ZnO morphologies elicited a supportive growth of gram-negative bacteria (Escherichia coli) in culture medium (until 28-35 μg/ml). But, all ZnO morphologies did elicit bactericidal effect on gram positive bacteria (Staphylococcus aureus or Staphylococcus epidermidis) both in culture medium (for 0-2.5 μg/ml) or when incorporated (5-20 wt.%) into UHMWPE. The bactericidal mechanisms were quantified for various ZnO morphologies via: (i) H2O2 production, (ii) Zn(2+) release, and (iii) the presence of surface oxygen vacancies. On one hand, where only ZnO(NP) elicited release of H2O2 in the absence of light, maximum Zn(2+) release was elicited by ZnO(D). Interestingly, when ZnO is incorporated as reinforcement (5-20 wt.%), its antibacterial action against E. coli was vividly observed due to selective proliferation of bacteria only on friendly UHMWPE matrix. Hence, luring bacteria on affable UHMWPE surface can be complemented with their targeted killing by ZnO present in composite.
authors.affiliation: Biomaterials Processing and Characterization Laboratory, Indian Institute of Technology Kanpur, Kanpur -208016, India.
authors.forename: Rajeev Kumar
authors.initials: RK
authors.lastname: Sharma
authors.affiliation: Amity Institute of Nanotechnology, Amity University, Noida, Uttar Pradesh - 201303, India.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Agarwal
authors.affiliation: Biomaterials Processing and Characterization Laboratory, Indian Institute of Technology Kanpur, Kanpur -208016, India. Electronic address: kbalani@iitk.ac.in.
authors.forename: Kantesh
authors.initials: K
authors.lastname: Balani
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D010316:Particle Size; D056951:Photoelectron Spectroscopy; D011095:Polyethylenes / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013054:Spectrophotometry, Atomic; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects; D015032:Zinc / Q000032:analysis; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D011095:Polyethylenes; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D015032:Zinc; D015034:Zinc Oxide
keywords: Antibacterial mechanism; Compression molding; Reactive oxygen species; Ultra high molecular weight polyethylene (UHMWPE); Zinc oxide (ZnO)