The influence of local structure and surface morphology on the antibacterial activity of silver-containing calcium borosilicate glasses

• Published in: Journal of non-crystalline solids 2014-11, Vol.404, p.98-103
• Main Authors: Ciceo Lucacel, R., Radu, T., Tătar, A.S., Lupan, I., Ponta, O., Simon, V.
• Format: Article
• Language: English
• Subjects: Antibacterial activity; Antiinfectives and antibacterials; Bacteria; Borosilicate glasses; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Escherichia coli; Exact sciences and technology; Glass; Local structure; Materials science; Morphology; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Scanning electron microscopy; Silver; Silver ions; Silver nanoparticles; Solid surfaces and solid-solid interfaces; Staphylococcus aureus; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Surface chemistry; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); X-ray photoelectron spectroscopy
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2014.08.004

A silver containing series of glasses starting from Ag-free 1.5B2O3·SiO·CaO parent glass and ending with 3mol% Ag2O was synthesized by the conventional melt quenching method and analyzed in order to correlate the composition and the structural peculiarities with the antibacterial effects. The structure and surface morphology of samples were characterized by X-ray diffraction (XRD), infrared (FTIR) and Raman spectroscopy, Scanning Electron Microscopy (SEM). X-ray photoelectron spectroscopy (XPS) was used to determine the nature of chemical bonding and the surface composition of the samples. The results indicate that all samples are vitreous and their local structure — mainly built by tetrahedral (BØ4‐), triangular (BØ3 and BØ2O−) borate species (Ø representing an oxygen atom bridging two boron atoms) and silicate Q1, Q2, Q3 units — is reactive to the silver oxide addition. Based on XPS data, both Ag+ and Ag0 ions are present on the surface of detected silver nanoparticles. Ag nanoparticles (AgNPs) embbeded in glasses were evaluated for their antimicrobial activity against the gram-positive and gram-negative bacteria, i.e. Staphylococcus aureus and Escherichia coli bacteria. The antibacterial effect of investigated samples increases simultaneously with the Ag2O content and AgNP dimension. The proposed mechanism is discussed in relation with the local structure, Ag+/Ag0 ratio and AgNP dimensions. •Melt-derived Ag2O–B2O3–SiO2–CaO bioactive glasses (x≤3mol%)•Silver influence on short range order, surface composition and morphology•Ag nanoparticles (AgNPs) developed on sample surface.•Antibacterial effect depends both on Ag2O content and sample structure.•Antibacterial effect increases with AgNPs dimension.