The antimicrobial and cellular proliferative potentials of some bioactive and biocompatible copper-containing glasses

Abstract

The bioactive glass system xCuO∙(100-x)[10B₂O₃∙30Na₂O∙60P₂O₅], where x = 0; 0.5; 1; 2; 4; 8; and 16 mol%, was prepared through the melt quenching method. Our aim was to assess the bioactivity, biocompatibility, antibacterial properties, and the action on cells in order to find a biomaterial that can be further used to repair damaged skin tissues. The glass structure was investigated through different spectroscopic techniques: Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), electron paramagnetic resonance (EPR), and energy dispersion spectroscopy (EDS). Also, the ionic release in liquids was assessed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Additionally, the biological behavior was evaluated through antibacterial and cytotoxicity assays. With the addition of copper to the glass samples, the structure of these is affected as indicated by FT-IR spectra changes. The UV–Vis data reveal the presence of copper in both oxidation states. The EPR spectra show that all samples doped with CuO exhibit absorptions characteristic for Cu²⁺ ions, located at sites with an axially distorted octahedral symmetry. The antibacterial effect of the glass samples with the highest concentrations of copper ions (i.e., 8 and 16 mol% CuO) was found to be the most efficient against both S. aureus and E. coli strains. The increase in the β-sheet amount in bovine serum albumin (BSA) and the decrease of its helical structure suggest the unfolding of protein after its attachment to the glass sample and further, confirms the biocompatibility of the system. The cell viability test shows that the use of a lower concentration of glass (i.e., 0.005 and 0.05 mg/dl) and a reduced number of copper cations stimulate the rate of keratinocyte cell proliferation in vitro. All obtained results prove that the investigated samples are biomaterials to be used in vitro in both hard and soft cell tissue repair and/or regeneration.