Antibacterial activity of nanostructured Ti-45S5 bioglass-Ag composite against Streptococcus mutans and Staphylococcus aureus

Mechanical alloying and annealing at 1150 °C for 2 h under an argon atmosphere were used to prepare Ti-45S5 bioglass nanocomposites. Ti-45S5 bioglass material was chemically modified by silver. The antibacterial activity of Ti-10% 45S5 bioglass nanocomposite containing silver against Streptococcus mutans and Staphylococcus aureus was studied. Nanocomposites were characterized by X-ray diffraction, scanning electron microscopy equipped with an electron energy dispersive spectrometer and transmission electron microscopy to evaluate phase composition, crystal structure and grain size. In vitro bacterial adhesion study indicated a significantly reduced number of Streptococcus mutans and Staphylococcus aureus on the bulk nanostructured Ti-45S5 bioglass-Ag plate surface in comparison to that on microcrystalline Ti plate surface. Nanostructured Ti-based biomaterials can be considered to be the future generation of dental implants.

Strengthening mechanisms in carbon nanotube reinforced bioglass composites

Carbon nanotube reinforced bioglass composites have been successfully synthesized by two comparative sintering techniques, i.e., spark plasma sintering （SPS） and conventional compaction and sinteirng. The composites show improved mechanical properties, with SPS technique substantially better than conventional compact and sintering approach. Using SPS, compared with the 45S5Bioglass matrix, the maximum flexural strength and fracture toughness increased by 159% and 105%, respectively. Enhanced strength and toughness are attributed to the interfacial bonding and bridging effects between the carbon nanotubes and bioglass powders during crack propagations.

Synthesis and Properties of Ag-doped Titanium-10 wt% 45S5 Bioglass Nanostructured Scaffolds

A new kind of biomedical Ti-45S5 Bioglass-Ag nanocomposites and their scaffolds with antibacterial function was developed by the introduction of 1.5 wt% Ag into the Ti-10 wt% 45S5 Bioglass matrix. The microstructure, hardness and corrosion resistance in Ringer solution of the Ag-doped Ti-45S5 glass were investigated. The Vickers hardness of the bulk Ti-10 wt% 45S5 Bioglass-1.5 wt% Ag nanocomposites reached 480 HVo.3. Contact angles of water on the micro- crystalline Ti and nanostructured Ti-10 wt% 45S5 Bioglass-1.5 wt% Ag sample were determined and show visible decrease from 55.2° to 49.6°. In vitro tests culture of normal human osteoblast cells showed very good cells proliferation, colonization and multilayering. In vitro bacterial adhesion study indicated a significantly reduced number of bacteria （Staphylococcus aureus） on the bulk nanostructured Ti-10 wt% 45S5 Bioglass-1.5 wt% Ag plate surface in comparison with that on microcrystalline Ti plate surface. Development of porous Ti-10 wt% 45S5 Bioglass-1.5 wt% Ag scaffolds aims in enhancing bone ingrowth and prosthesis fixation.

Superior biocompatibility and comparable osteoinductive properties: Sodium-reduced fluoride-containing bioactive glass belonging to the CaO–MgO–SiO2 system as a promising alternative to 45S5 bioactive glass

Bioactive glasses(BGs)are promising bone substitute materials.However,under certain circumstances BGs such as the well-known 45S5 Bioglass®(composition in wt%:45.0 SiO2,24.5 Na2O,24.5 CaO,6.0 P2O5)act cytotoxic due to a strong increase in pH caused by a burst release of sodium ions.A potential alternative is a sodiumreduced fluoride-containing BG belonging to the CaO–MgO–SiO2 system,namely BG1d-BG(composition in wt%:46.1 SiO2,28.7 CaO,8.8 MgO,6.2 P2O5,5.7 CaF2,4.5 Na2O),that has already been evaluated in-vitro,in-vivo and in preliminary clinical trials.Before further application,however,BG1d-BG should be compared to the benchmark amongst BGs,the 45S5 Bioglass®composition,to classify its effect on cell viability,proliferation and osteogenic differentiation of human mesenchymal stem cells(MSCs).Therefore,in this study,the biocompatibility and osteogenic potential of both BGs were investigated in an indirect and direct culture setting to assess the effect of the ionic dissolution products and the BGs’physical presence on the cells.The results indicated an advantage of BG1d-BG over 45S5 Bioglass®regarding cell viability and proliferation.Both BGs induced an earlier onset of osteogenic differentiation and accelerated the expression of late osteoblast marker genes compared to the control group.In conclusion,BG1d-BG is an attractive candidate for further experimental investigation.The basic mechanisms behind the different impact on cell behavior should be assessed in further detail,e.g.by further alteration of the BG compositions.