Characterization and in-vitro behaviour of bioactive glass / polymeric composites

Chitosan biopolymer characterizes osteoinductive functions and it can be utilized in combination with other bioactive materials that enhances tissue regenerative efficacy and osteoconductivity. Another material of interest is bioactive glass [BG] [45S5] that characterizes its ability to bond to bone and soft tissues very quickly as a result of high level of its surface reactivity. In this study, BG was combined with chitosan to produce novel bio-composites having properties analogous to human cancellous bone. The affinity between BG filler and polymer matrix has been proved by X -ray diffraction [XRD], Fourier transform infrared [FT-IR] and Thermogravimetric analysis [TGA] techniques. The results confirmed that homogeneity and integration between BG filler and polymer matrix especially the composite containing smaller particle size of BG is achieved. Also, the formation of calcium phosphate layer onto the surface of composite was detected post-immersion in simulated body fluid [SBF] for different periods up to 21 days at 37°C and pH 7.4. Conclusions prove that the presence of smaller particle size of BG filler into the polymeric matrix leads to more effective reinforcement of the composite and increased the bioactivity via high formation of carbonated apatite layer onto the composite surface. These biocomposites are promised for bone replacement and scaffold for tissue engineering applications

Preparation, characterization and in-vitro studies of hydroxyapatite and biphasic of hydroxyapatite-tricalcium phosphate /co- polymeric biocomposites

Calcium phosphates with clinical applications constitute an interesting field of research and development in the production of useful biomaterials for implant fabrication and/or fixation. They exhibit very good biocompatibility and bone integration qualities. In this work hydroxyapatite [HAp] was prepared by precipitation method, while the biphasic hydroxyapatite/beta-tricalcium phosphate [H A/ beta-TCP] was prepared by heating the prepared HAp at 900°C for 5 hr in air. To improve bioactivity both HAp and HAp/ beta-TCP fillers were loaded onto grafted chitosan with two monomers, hydroxyethylmethacrylate [HEMA] and methylmethacrylate [MMA] during copolymcrization process. X-ray diffraction analysis revealed the HAp and biphasic HAp / beta-TCP phases for the prepared samples and proved integration and coating between these fillers and the copolymer. Thermogravimetric analyses of composites showed the attached layer of copolymer onto the surface of fillers particles were 59.818 and 37% for HAp and HAp/ beta-TCP composites, respectively. SEM and FTIR for fillers and composites confirmed the compatibility between the tillers and copolymer. In vitro studies were conducted by immersing the composites in simulated body fluid [SBF] at 37 °C for various time-points. Post-immersion results showed the formation of carbonated apatite layer on the surface of both fillers and their composites especially for HA tiller and it's composite. Also, deposition of Ca[2+] and PO[4][3-] ions onto the surface was achieved for HA filler and its composite more than biphasic filler and its composite as confirmed by FT-IR data. Therefore, these biocompoites can be used as bone substitutes or tissue engineering applications