title: TiO2 nanotube composite layers as delivery system for ZnO and Ag nanoparticles - an unexpected overdose effect decreasing their antibacterial efficacy.
abstract: Enhancement of biocompatibility and antibacterial properties of implant materials is potentially beneficial for their practical value. Therefore, the use of metallic and metallic oxide nanoparticles as antimicrobial coatings components which induce minimized antibacterial resistance receives currently particular attention. In this work, TiO2 nanotubes layers loaded with ZnO and Ag nanoparticles were designed for biomedical coatings and delivery systems and evaluated for antimicrobial activity. TiO2 nanotubes themselves exhibited considerable and diameter-dependent antibacterial activity against planktonic Staphylococcus epidermidis cells but favored bacterial adhesion. Loading of nanotubes with moderate amount of ZnO nanoparticles significantly diminished S. epidermidis cell adhesion and viability just after 1.5h contact with modified surfaces. However, an increase of loaded ZnO amount unexpectedly altered the structure of nanoparticle-nanolayer, caused partial closure of nanotube interior and significantly reduced ZnO solubility and antibacterial efficacy. Co-deposition of Ag nanoparticles enhanced the antibacterial properties of synthesized coatings. However, the increase of ZnO quantity on Ag nanoparticles co-deposited surfaces favored the adhesion of bacterial cells. Thus, ZnO/Ag/TiO2 nanotube composite layers may be promising delivery systems for combating post-operative infections in hard tissue replacement procedures. However, the amount of loaded antibacterial agents must be carefully balanced to avoid the overdose and reduced efficacy.
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. Electronic address: aroguska@ichf.edu.pl.
authors.forename: A
authors.initials: A
authors.lastname: Roguska
authors.affiliation: Chair Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodzki 1, 20-093 Lublin, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Belcarz
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Pisarek
authors.affiliation: Chair Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodzki 1, 20-093 Lublin, Poland.
authors.forename: G
authors.initials: G
authors.lastname: Ginalska
authors.affiliation: Faculty of Material Science and Engineering, Warsaw University and Technology, Wołoska 141, 02-507 Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Lewandowska
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000737:chemistry; D001419:Bacteria; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004058:Diffusion; D004338:Drug Combinations; D004347:Drug Interactions; D004357:Drug Synergism; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D053769:Nanocapsules / Q000008:administration & dosage / Q000737:chemistry* / Q000648:ultrastructure; D053761:Nanocomposites / Q000008:administration & dosage / Q000737:chemistry / Q000648:ultrastructure; D010316:Particle Size; D012834:Silver / Q000008:administration & dosage* / Q000737:chemistry; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000502:physiology; D014025:Titanium / Q000737:chemistry*; D015034:Zinc Oxide / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D053769:Nanocapsules; C009495:titanium dioxide; D012834:Silver; D014025:Titanium; D015034:Zinc Oxide
keywords: Ag nanoparticles; Antibacterial properties; Overdose; Staphylococcus epidermidis; TiO(2) nanotubes; ZnO nanoparticles