Selenium nanoparticles incorporated into titania nanotubes inhibit bacterial growth and macrophage proliferation

Abstract

Since implants often fail due to infection and uncontrolled inflammatory responses, we designed an in vitro study to investigate the antibacterial and anti-inflammatory properties of titanium dioxide nanotubes (TNTs) incorporated with selenium nanoparticles (SeNPs). Selenium incorporation was achieved by the reaction of sodium selenite (Na2SeO3) with glutathione (GSH) under a vacuum in the presence of TNTs. Two types of bacteria and macrophages were cultured on the samples to determine their respective antibacterial and anti-inflammatory properties. The results showed that the TNT samples incorporating SeNPs (TNT-Se) inhibited the growth of Escherichia coli and Staphylococcus aureus compared to unmodified TNTs, albeit the SeNP concentration still needs to be optimized for maximal effect. At their maximum effect, the TNT-Se samples reduced the density of E. coli by 94.6% and of S. aureus by 89.6% compared to titanium controls. To investigate the underlying mechanism of this effect, the expression of six E. coli genes were tracked using qRT-PCR. Results indicated that SeNPs weakened E. coli membranes (ompA and ompF were down-regulated), decreased the function of adhesion-mediating proteins (csgA and csgG were progressively down-regulated with increasing SeNP content), and induced the production of damaging reactive oxygen species (ahpF was up-regulated). Moreover, TNT-Se samples inhibited the proliferation of macrophages, indicating that they can be used to control the inflammatory response and even prevent chronic inflammation, a condition that often leads to implant failure. In conclusion, we demonstrated that SeNP-TNTs display antibacterial and anti-inflammatory properties that are promising for improving the performance of titanium-based implants for numerous orthopedic and dental applications.

<p>Green Synthesized BSA-Coated Selenium Nanoparticles Inhibit Bacterial Growth While Promoting Mammalian Cell Growth</p>

“…Conversely, SeNPs were ineffective against both E. coli species. Reports in the literature have contrary effects of SeNP on E. coli; some researchers found antibacterial efficacy 6,32,33 while others did not. 29,34,35 At this moment, there is no conclusive mechanism for the bactericidal activity of SeNPs.…”

“…Liu et al found that SeNP loaded into an anodized titanium nanotube repelled E. coli growth and identified three modes of action: membrane disruption, damage to adhesion-mediating proteins, and reactive oxygen species (ROS) generation. 6 However, Zonaro found that the amount of ROS generated by SeNPs (221.1-345.2 nm) did not correlate with the bacterial inhibition. 32 In addition, prior studies with SeNP-treated Staphylococcus epidermidis, a Gram-positive bacterium (submitted work) did not show damaged bacterial membranes, suggesting membrane disruption was not the primary mode of antibacterial activity and may account for why the SeNPs were ineffective against E. coli in this study.…”

“…3 One promising area of research is the application of nanotechnology towards selenium fabrication and use. [6][7][8][9][10] Nanoparticles (NPs) are particularly suitable as they possess high surface area to volume ratios, increased surface area, and increased interactions with biological targets, leading to higher availability and absorption by the host. [11][12][13] In addition, selenium NPs (SeNPs) possess lower toxicity than their elemental form; in mice, the LD 50 of selenomethionine was 25.6 mg Se/kg compared with 92.1 mg Se/kg for SeNPs.…”

Macrophage‐Targeted Isoniazid–Selenium Nanoparticles Promote Antimicrobial Immunity and Synergize Bactericidal Destruction of Tuberculosis Bacilli

“…aureus, and S . epidermidis , and protect against bacterium‐mediated tissue injury . Concurrently, as macrophages highly express mannose receptors, mannose‐decorated nanoparticles can serve as excellent carriers delivering drugs into macrophages .…”

Preparation, Physico-chemical Characterization and Photocatalytic Properties of Se Doped TiO2 Nanoparticles

“…Hydrothermal reaction method was applied for the production of Se-doped TiO2 nanoparticles, according to Zavala et al [16] and Liu et al [17].Briefly, 7 g of TiO2 power (Sigma-Aldrich, CAS No-13463-76-7) was dissolved in 70 mL NaOH10N, by continuously stirring at 30°C, for 2 hours. The solution was introduced in autoclave at 1400 ͦ C for 24 hours.…”