Bactericidal multilayer fibrous titanium phosphate nanocomposites with embedded silver nanoparticles by optimized
Tetiana Hubetska1,2, Olena Khainakova3, Sara González-Fernández1
1Nanomaterials and Nanotechnology Research Center (CINN-CSIC), University of Oviedo Av. de La Vega 4-6 El Entrego 33940 Spain.
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In this study, novel nanocomposites based on fibrous titanium phosphate (π-TiP) functionalized with biosynthesized silver nanoparticles (AgNPs) were successfully developed, and their bactericidal potential was systematically evaluated. The nanocomposites (TiP@AgNPs) were prepared via the in situ treatment of π-TiP nanofibres with AgNPs synthesized using Melissa officinalis leaf extract and two silver(i) precursors (AgNO3 and CH3COOAg) at various concentrations (1 mM, 5 mM, and 10 mM). The biosynthesized AgNPs were found to be spherical (10-15 nm), exhibiting a formation rate and size directly dependent on the silver(i) precursor. Significantly higher reaction rates were achieved with the use of CH3COOAg. Additionally, the as-prepared AgNPs exhibited nucleoprotective properties due to the formation of a 'core-shell' structure, which prevented the aggregation of the resulting nanoparticles. TEM images of TiP@AgNPs nanocomposites indicate a uniform distribution of monodisperse AgNPs on the surfaces of fibres. The amount of AgNPs loaded onto fibrous surfaces was found to be directly proportional to the initial concentration of the AgNPs. At the same time, FTIR and TGA/MS methods confirmed the presence of Melissa leaf extract components in the fibre cavities and on the nanoparticle surfaces. In vitro antibacterial tests demonstrated that the obtained nanocomposites possessed potent, dose- and time-dependent antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Furthermore, the nanocomposites demonstrated strain-specific selectivity against the Gram-negative Escherichia coli compared to the Gram-positive Staphylococcus aureus. Finally, the TiP@AgNPs nanocomposite synthesized using 10 mM of CH3COOAg exhibited the most efficient bactericidal performance while remaining within the non-toxic threshold for bactericidal materials. Thus, these nanocomposites hold great promise as highly effective and controllable antibacterial agents for biomedical applications.
