Chen Q (2015)
Publication Type: Thesis
Subtype: other
Publication year: 2015
URI: https://nbn-resolving.org/urn:nbn:de:bvb:29-opus4-64927
In spite of notable success of metallic orthopedic prosthesis in clinical, their long-term survivability remains a major challenge due to the lack of osteoconductivity and risks associated with post-surgery infections and surface corrosion. Modification of implant surfaces with bioactive materials and antimicrobial agents is being intensively investigated to prevent these negative effects. In this project, electrophoretic deposition (EPD) as a convenient coating technique has been developed to generate different combinations of biopolymer-bioceramic composite coatings on metallic substrates with the aim of enhancing bioactive characters and minimizing infections. Bioactive ceramics, e.g. 45S5 bioactive glass (BG), hydroxyapatite (HA), and phosphate glass fibers were applied in this study. There are promising bone substitute materials which were investigated to support the bioactive character of the coating for an enhanced bone-to-implant interaction. The polymer components considered in this research project, e.g. alginate, chitosan, cellulose nanocrystals (CNCs), polyacrylic acid (PAA) and polyvinyl alcohol (PVA), will not only strengthen the bonding of bioceramics coating to the surface of the implant, but also offer the possibility to control the in situ release of dissolution products and can accelerate the attachment of biomolecules and cells by the presence of functional groups. A series of composite coatings with different combination of inorganic fillers and biopolymer matrix were successfully fabricated by EPD from aqueous based suspensions at room temperature. The composite coating systems produced and characterized in this project were alginate-BG, alginate-PVA-BG, CNCs-BG, PAA-phosphate glass fiber, Alginate-PHBV microsphere and HA based multilayers. The co-deposition mechanisms were experimentally investigated and the coating properties were comprehensively assessed by means of relevant material characterizations and cell biology tests. In addition, due to the temperate coating conditions offered by EPD, specific drug molecules (antibiotic, enzyme and growth factor) were able to be incorporated into the coating structure by two methods: (i) direct co-deposition exploiting the interactions between drug molecules with the charged biopolymer molecules, (ii) pre-loading of the drug into a biodegradable polymer microspheres, and co-deposition with the biopolymer matrix material. The coating properties, including degradation, adhesion and drug release profiles, which are key factors for an effective and sustained antibacterial effect, were optimized and validated. A multilayer coating, considered to impart the osteoconductivity and antibacterial properties simultaneously, was successfully fabricated via a combination of EPD and layer by layer deposition. The aim of this project, which focused on exploiting the EPD technique to fabricate biomedical coatings with specific functions, oriented fiber structures and free-standing membranes for emerging biomedical applications, was achieved and a series of new coating systems, well characterized and exhibiting combination of favorable properties, are thus available for further applications and dedicated in vivo evaluations.
APA:
Chen, Q. (2015). Electrophoretic Deposition of Composite Coatings with Bioactive Character and Drug Delivery Capability.
MLA:
Chen, Qiang. Electrophoretic Deposition of Composite Coatings with Bioactive Character and Drug Delivery Capability.2015.
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