چكيده به لاتين
The purpose of this project is to prepare nanocomposite pastes consisting of bioactive glass components, polymer solutions containing chitosan and gelatin, crosslinker (GPTMS) and to study the physical, rheological and biological properties of the prepared composites. Polymer solution and crosslinker amount were selected as variables.
First, bioactive glass (BG1) 64SiO2.31CaO.5P2O5, (BG2) 64SiO2.27CaO.4MgO.5P2O5 were synthesized by open acid sol-gel method and the properties of the prepared powder were determined by XRD, FTIR, BET and SEM analyzes. Bioactive glass powder was prepared with polymer solutions of chitosan and gelatin with concentration (3 w/v) and rheological properties in oscillation, injectability, leaching resistance and calcium phosphate phase formation behavior in simulated body solution (SBF) with The passage of time was assessed using EDXA, XRD, FTIR and SEM techniques.
The results showed that synthesized glass powder (BG1) has a specific surface area (m2/g) of 123.139, average pore diameter (nm) 18.217 and pore volume (cm3/g) 0.602 and glass powder BG2 has a specific surface area of 109.104 (m2/g), a multiple distribution in the pore size of this glass can be seen so that the average pore diameter (nm) is 23.0636 and the pore volume (cm3/g) is 0.340. In fact, by adding magnesium to the glass composition, the specific surface area decreased, the diameter and volume of the cavities increased.
The paste obtained from a mixture of glass (BG1), chitosan solution and gelatin solution has a thin shear behavior. By adding chitosan to the paste containing gelatin, the maximum mixed viscosity increased from 8.88 × 10 Pa.s to 3.38 × 102 Pa.s, so that only 3.82 × 105 Pa.s was measured in the chitosan paste. By adding chitosan to the composite paste, the injection force in the 2 mm needle syringe increased from about 5 N to 20 N and the injectability decreased from 100% to 53%. After 14 days of immersion in SBF solution, a layer of apatite calcium phosphate with calcite was formed on the surface of the paste, which indicates the bioactivity of nanocomposite pastes. The leaching resistance of the pastes was evaluated so that by adding GPTMS to the paste, the leaching resistance of the gelatin-containing pastes was improved, while the maximum mixed viscosity of all pastes reached more than 105 Pa.s, the rheological behavior of gelatin-containing pastes. Regularly, the injectability of chitosan-containing pastes was drastically reduced due to the fuzzy separation phenomenon, and the storage modulus of all pastes in the range was 0.1-1000 S-1 times larger than its dissipation modulus. With increasing concentration of GPTMS, the mixed viscosity increased again.
In BG2 pastes, with increasing GPTMS value, the mixed viscosity in the chitosan-containing paste increased from Pa.s 6.09 x 104 to 1.14 x 105. In gelatin-containing paste, only the mixed viscosity increased from Pa.s 4.06 x 104 to 3.51 x 105 increased. While the cohesion of the structure increased with the addition of magnesium, the formation of calcite was generally controlled so that after 14 days of immersion in SBF solution, the calcite was completely dissolved and turned into apatite.
Mechanical strength is increased by adding 10 wt.% or 20 wt.% by weight of GPTMS. In addition, the polymers did not increase degradation because the weight loss was> 10% after 30 days under physiological conditions. BG2-gelatin-20 wt.% GPTMS composites showed the highest compressive strength (4.8 ± 0.5 MPa) compared to 100% BG control (1.9 ± 0.1 MPa). Cell compatibility with human mesenchymal stem cells (hMSC), osteoblasts and endothelial cells was demonstrated. The presence of 20 wt.% GPTMS causes antibacterial properties and thus prevents joint pathogens of Staphylococcus aureus and Staphylococcus epidermidis. Finally, hMSC ossification was successfully supported in a 3-D model demonstrated by alkaline phosphatase release and expression of osteogenic genes.
In general, composites made of bioactive glass, chitosan solution, gelatin solution and GPTMS can be used as bone substitutes. Of course, bioactivity, injectability and leaching resistance in these composites depend on the composition, type of polymer solution and concentration of GPTMS.
