Li W (2015)
Publication Type: Thesis
Subtype: other
Publication year: 2015
URI: https://nbn-resolving.org/urn:nbn:de:bvb:29-opus4-64896
Bone tissue engineering is a rapidly developing interdisciplinary field. An effective approach to bone tissue engineering aims to restore the function of damaged bone tissue or to regenerate bone tissue with the aid of scaffolds made from engineered biomaterials. The scaffolds should act as temporary matrices for cell attachment, proliferation, migration, differentiation and extracellular matrix deposition, with consequent bone ingrowth until the new bone tissue is totally restored or regenerated.Highly porous 45S5 bioactive glass (BG) scaffolds with suitable pore size and interconnected pore structure are promising candidates for bone tissue engineering applications due to their bioactivity, biocompatibility, osteogenic and potential angiogenic effects. In this work, to ensure the mechanical competence of the 45S5 BG scaffolds developed by foam replication method, their strength and toughness were improved by applying various polymer coatings. Among the used polymer coatings, genipin cross-linked gelatin (GCG) exhibited the most significant strengthening and toughening effects. Besides the strength and toughness, the stiffness of 45S5 BG scaffolds was adjusted by using polymer coatings and further crosslinking treatment in order to meet the property of human cancellous bone. Furthermore, all polymer coatings did not significantly affect the pore size, porosity and pore interconnectivity of the 45S5 BG scaffolds, and the bioactivity was maintained in the developed polymer coated scaffolds.In order to endow the scaffolds with controlled and sustained drug delivery function for preventing or treating potential bacterial infections or bone diseases, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microspheres with suitable particle size were prepared by emulsion solvent extraction/evaporation method. Both hydrophilic and hydrophobic drugs with anti-bacterial or anti-osteoporosis effects were successfully loaded into the PHBV microspheres. The PHBV microsphere coated 45S5 BG scaffolds released the drug in a more controlled and sustained manner as compared to not only the uncoated scaffolds but also to the PHBV film coated scaffolds.In this work, polyguanidine, as an example of a biocidal cationic polymer, was used as an addition to antibiotics for antibacterial purpose due to its potential to overcome antibiotic resistance. The GCG coated 45S5 BG scaffolds were antibacterial against both Gram-positive and Gram-negative bacteria after the incorporation of polyguanidine. In vitro biocompatibility tests indicated that osteoblast-like MG-63 cells could attach, spread and proliferate on these scaffolds.Moreover, PHBV microspheres were used as drug delivery vehicle in polymer based composite materials for tissue engineering applications. Chitosan-45S5 BG-PHBV microsphere composite membranes were prepared by solution casting method. The incorporation of 45S5 BG particles and PHBV microspheres endowed the chitosan membranes with bioactivity, sustained drug release function and favorable cell response.In summary, the developed bioactive 45S5 BG-based composite scaffolds with superior mechanical properties, favorable drug release profile and cell biocompatibility are promising candidates for bone tissue engineering applications. In addition, PHBV microspheres developed in this work are effective drug carriers with high potential in the biomedical field.
APA:
Li, W. (2015). 45S5 Bioactive Glass-Based Composite Scaffolds with Polymer Coatings for Bone Tissue Engineering Therapeutics.
MLA:
Li, Wei. 45S5 Bioactive Glass-Based Composite Scaffolds with Polymer Coatings for Bone Tissue Engineering Therapeutics.2015.
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