Fabrication and characterization of Bioactive/Biodegradable materials for tissue engineering

One of the main concerns in public healthcare in both developed and developing countries which cause handicap, physical disability and patient chronic pain is currently related to musculoskeletal problems and, in particular, to osteoarticular diseases. Since these diseases and induced defects affect millions of people worldwide, treatment of bone tumors, traumatology, osteoporosis and others pathologies, especially for aging populations, gained prime importance. In the past decades, great effort from scientific/medical society has been addressed to the development of safe reliable synthetic bone graft materials as alternative to allo- and autografts. The use of latter ones is usually associated with transmission complications as well as with immunological rejection and morbidity. Calcium phosphates, in general, and in particular, hydroxyapatite, nanocrystalline biomimetic apatites and amorphous calcium phosphates, as well as bioactive glasses, recently gained much attention as promising materials for the treatment of non-self healing bone defects. However, despite undeniable advantages such as biocompatibility, non-toxicity, and good bioactivity, clinical applications of these materials are still limited. In the present thesis, beyond the state of art, it was attempted to tackle various problems related to the development and essential systematic characterization of innovative materials for hard and soft tissue engineering. In the first part of the study, bioactivity of novel low alkaline glass using simulated body fluid (SBF) was assessed. Specifically, the effects produced by devitrification phenomena which take place during the consolidation of amorphous glass powder on the biological behavior of the resulting material was considered. The second part of the study was dedicated to the evaluation of biological compatibility of different calcium phosphate/bioactive glass composites. To this purpose, different composites obtained by combining of hydroxyapatite with a low alkaline bioactive glass were first sintered into bulk discs via innovative spark plasma sintering technique and then exposed to the cell tests using murine long bone osteocyte-like immortalized cell line. The results were compared with the findings deriving from the SBF tests performed previously. The third part of the thesis was focused of the development of novel functionally graded materials in the calcium hosphate/bioactive glass system. In the fourth part of the thesis, the synthesis, sintering and physico-chemical characterization of highly carbonated magnesium-doped amorphous calcium phosphates, a novel family of bone substitute materials, was reported and discussed. Fifth part of this thesis deals with the fabrication and characterization of fibrous polymer/bioactive glass composite scaffolds for soft tissue engineering. Recently, it has been shown that bioactive glasses are able not only directly bond with the bone, but they also possess angiogenesis potential (bioactive glass ion dissolution products can induce new blood vessels regeneration). The latter property is crucial for the treatment of soft tissue wounds. The extension of bioactive glass application to areas such as peripheral nerve repair, healing of burn injures and chronic wound healing attracted much attention lately. In the present study, fibrous scaffolds from different biodegradable polymers coupled with bioactive glasses were fabricated using electrospinning technique. Biological performances in a presence of bone murine stromal cells as well as mechanical properties of prepared scaffold were investigated.