title: Ion exchange defines the biological activity of titanate nanotubes.
abstract: One-dimensional titanate nanotubes (TiONTs) were subjected to systematic ion exchange to determine the impact of these modifications on biological activities. Ion exchanged TiONTs (with Ag, Mg, Bi, Sb, Ca, K, Sr, Fe, and Cu ions) were successfully synthesized and the presence of the substituted ions was verified by energy dispersive X-ray spectroscopy (EDS). A complex screening was carried out to reveal differences in toxicity to human cells, as well as in antibacterial, antifungal, and antiviral activities between the various modified nanotubes. Our results demonstrated that Ag ion exchanged TiONTs exerted potent antibacterial and antifungal effects against all examined microbial species but were ineffective on viruses. Surprisingly, the antibacterial activity of Cu/TiONTs was restricted to Micrococcus luteus. Most ion exchanged TiONTs did not show antimicrobial activity against the tested bacterial and fungal species. Incorporation of various ions into nanotube architectures lead to mild, moderate, or even to a massive loss of human cell viability; therefore, this type of biological effect exerted by TiONTs can be greatly modulated by ion exchange. These findings further emphasize the contribution of ion exchange in determining not only the physical and chemical characteristics but also the bioactivity of TiONT against different types of living cells.
authors.affiliation: Department of Applied and Environmental Chemistry, University of Szeged, Szeged, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Rónavári
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary.
authors.forename: Dávid
authors.initials: D
authors.lastname: Kovács
authors.affiliation: Department of Microbiology, University of Szeged, Szeged, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Vágvölgyi
authors.affiliation: Department of Applied and Environmental Chemistry, University of Szeged, Szeged, Hungary.|MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, Szeged, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Kónya
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary.
authors.forename: Mónika
authors.initials: M
authors.lastname: Kiricsi
authors.affiliation: Department of Microbiology, University of Szeged, Szeged, Hungary.
authors.forename: Ilona
authors.initials: I
authors.lastname: Pfeiffer
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007474:Ion Exchange; D053768:Metal Nanoparticles; D008826:Microbial Sensitivity Tests; D016982:Micrococcus luteus / Q000187:drug effects; D043942:Nanotubes / Q000633:toxicity*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects; D013052:Spectrometry, X-Ray Emission; D014025:Titanium / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D014025:Titanium
keywords: Antimicrobial activity; Ion exchange; Titanate nanotubes; Toxicity