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The study aimed at preparing Ag-doped bioactive glass (BG) nanoparticles containing 5 wt% Ag2O using a new modified Stober method (Ag-BGm) and the conventional sol-gel method (Ag-BGsg). The aim of employing the new Ag-doping mechanism is to implement a relatively short process to incorporate higher concentration of silver (Ag+) ions in an attempt to combine the antibacterial activity of silver with the bioactivity of BG. SEM and TEM micrographs showed that Ag-BGm nanoparticles were mondispersed, and spherical, while Ag-BGsg nanoparticles were formed of highly porous irregular agglomerated particles. A significantly higher silicon, calcium and silver ions release from the Ag-BGsg was evident, as compared to Ag-BGm, in deionized water (DIW). In vitro bioactivity test showed rapid bioactive properties of Ag-BGsg in simulated body fluid (SBF), as compared to Ag-BGm. Both BGs showed antibacterial effect against E. coli O157: H7 wild type strain 93111 and S. aureus ATCC 25923 as evident by the disc diffusion assay, but Ag-BGsg showed significantly higher mean inhibition zone compared to Ag-BGm. It may be concluded that both Ag-BGsg and Ag-BGm has the potential to be used as bone substitute materials with the Ag-BGsg being more promising due to its high bioactivity and antibacterial effect.

Boron is considered to influence the performance of several metabolic enzymes and boron deficiency is associated with impaired growth and abnormal bone development. As such, boron is a beneficial bioactive element for animals and humans. It is also well known that boron stimulates wound healing and improves bone health. The addition of boron in different proportions to bioactive glasses has significant effects on glass structure, glass processing parameters, biodegradability, biocompatibility, bioactivity and cytotoxicity. Different compositions of bioactive glasses (BGs) containing boron, including boron-doped, borosilicate and borate glasses, are being investigated for bone and soft tissue engineering under the premise that these BGs are suitable carriers of boron, indicating controlled release of B species in the biological environment. This paper reviews up to date research and applications of borate, borosilicate, and boron doped silicate and phosphate BGs focussing on their physical, structural, degradation and biological properties for hard and soft tissue regeneration.

We report for the first time on the combination of polymer replication method and flock technology to produce 45S5 bioactive glass (45S5 BG) scaffolds with a fibrous surface morphology suitable for tissue engineering (TE). In order to develop a fibrous morphology on the surface of the scaffolds, electroflocking was used with BG scaffolds serving as the substrate. Gelatin was used as the adhesive and short polyamide (PA) fibers were electroflocked on the top surface to produce scaffolds with anisotropic properties. In order to improve the stability of the adhesive (gelatin) and to create a better bonding between the fibers and the adhesive, a crosslinking step was carried out. The porosity on the surface could be tailored by varying the flocking time which, in turn, was shown to influence the packing density of the fibers. In vitro bioactivity study in simulated body fluid (SBF) was carried out and complete mineralization of the scaffold, including on the PA fibers, was detected and characterized using various techniques.

Bioactive glasses (BG) are versatile materials for various biomedical applications, including bone regeneration and wound healing, due to their bone bonding, antibacterial, osteogenic, and angiogenic properties. In this study, we aimed to enhance the antibacterial activity of SiO2-CaO mesoporous bioactive glass nanoparticles (MBGN) by incorporating silver (Ag) through a surface modification approach. The modified Ag-containing nanoparticles (Ag-MBGN) maintained spherical shape, mesoporous structure, high dispersity, and apatite-forming ability after the surface functionalization. The antibacterial activity of Ag-MBGN was assessed firstly using a planktonic bacteria model. Moreover, a 3D tissue-engineered infected skin model was used for the first time to evaluate the antibacterial activity of Ag-MBGN at the usage dose of 1 mg/mL. In the planktonic bacteria model, Ag-MBGN exhibited a significant antibacterial effect against both Pseudomonas aeruginosa and Staphylococcus aureus in comparison to non-engineered (Ag-free) MBGN and the blank control. Moreover, Ag-MBGN did not show cytotoxicity towards fibroblasts at the usage dose. However, in the 3D infected skin model, Ag-MBGN only demonstrated antibacterial activity against S. aureus whereas their antibacterial action against P. aeruginosa was inhibited. In conclusion, surface modification by Ag incorporation is a feasible approach to enhance the antibacterial activity of MBGN without significantly impacting their morphology, polydispersity, and apatite-forming ability. The prepared Ag-MBGN are attractive building blocks for the development of 3D antibacterial scaffolds for tissue engineering.