Dinuclear copper(I) complexes of N-methylbenzothiazole-2-thione: synthesis, structures, antibacterial activity and DNA interaction

Antibacterial properties and regenerative potential of Sr2+ and Ce3+ doped fluorapatites; a potential solution for peri-implantitis

Scaffolds and implants in orthopaedics and regenerative dentistry usually fail because of bacterial infections. A promising solution would be the development of biomaterials with both significant regenerative potential and enhanced antibacterial activity. Working towards this direction, fluorapatite was synthesised and doped with Sr2+ and Ce3+ ions in order to tailor its properties. After experiments with four common bacteria (i.e. E. Coli, S. Aureus, B. Subtilis, B. Cereus), it was found that the undoped and the Ce3+ doped fluorapatites present better antibacterial response than the Sr2+ doped material. The synthesised minerals were incorporated into chitosan scaffolds and tested with Dental Pulp Stem Cells (DPSCs) to check their regenerative potential. As was expected, the scaffolds containing Sr2+-doped fluorapatite, presented high osteoconductivity leading to the differentiation of the DPSCs into osteoblasts. Similar results were obtained for the Ce3+-doped material, since both the concentration of osteocalcin and the RUNX2 gene expression were considerably higher than that for the un-doped mineral. Overall, it was shown that doping with Ce3+ retains the good antibacterial profile of fluorapatite and enhances its regenerative potential, which makes it a promising option for dealing with conditions where healing of hard tissues is compromised by bacterial contamination.

Design of a Multifunctional Nanoengineered PLLA Surface by Maximizing the Synergies between Biochemical and Surface Design Bactericidal Effects

Nanotechnology, the manipulation of matter on atomic, molecular, and supramolecular scales, has become the most appealing strategy for biomedical applications and is of great interest as an approach to preventing microbial risks. In this study, we utilize the antimicrobial performance and the drug-loading ability of novel nanoparticles based on silicon oxide and strontium-substituted hydroxyapatite to develop nanocomposite antimicrobial films based on a poly(l-lactic acid) (PLLA) polymer. We also demonstrate that nanoimprint lithography (NIL), a process adaptable to industrial application, is a feasible fabrication technique to modify the surface of PLLA, to alter its physical properties, and to utilize it for antibacterial applications. Various nanocomposite PLLA films with nanosized (black silicon) and three-dimensional (hierarchical) hybrid domains were fabricated by thermal NIL, and their bactericidal activity against Escherichia coli and Staphylococcus aureus was assessed. Our findings demonstrate that besides hydrophobicity the nanoparticle antibiotic delivery and the surface roughness are essential factors that affect the biofilm formation.