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Title: Developing silica based nanocomposites for dental applications using Bombyx mori silk
Author: Zafar, M. S.
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 2011
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A significant amount of research is being carried out on natural Bombyx mori (BM) silk which has gained remarkable popularity for biomedical applications in recent years. The main objective of this thesis is concerned with the development of a new silk based material with improved properties for dental tissue repair and dentin regeneration. In the first phase, research was carried out to study the chemistry and kinetics of silica formation and to assess the effects of silk proteins on the mechanical and functional properties of nanocomposite materials. A novel method was developed to separate different silk fractions (heavy chain fibroin and light chain fibroin) from natural silk using formic acid. Silk and its fractions were regenerated for use in gelation studies and fabricating nanocomposites by adding silica. The silica was added using, hydrolysed tetraethoxy silane (TEOS) to condense into gelling silk solutions or by adding pre-condensed silica nanoparticles (14-350 nm), prepared using a modified Stbber method. Silk solutions were characterised using viscometery, dynamic light scattering (DLS) and electrophoresis (SDS-PAGE). In the second phase, silk based nanocomposites were fabricated using electrospinning and gelation routes. The fabricated nanocomposite materials were characterised using scanning electron microscopy (SEM), elemental analysis (EDX), Fourier transform infra-red spectroscopy (FTIR), Thermogravimetric analysis (TGA) and compressibility testing. Both silk fractions (heavy chain fibroin and light chain fibroin) have entirely different structural, conformational and functional properties and can be regenerated using ionic solutions. Heavy chain silk due to its unique properties such as high hydrophobic amino acid domains (repeats of GAGAGS or GAGAGY) resulted in comparatively more p-sheet content, producing different solution as well as materials properties. Silk fractions were electrospun and the morphology of electrospun fibres was affected by the relative proportion of heavy and light chain silk in the solutions. Similar results were found for materials prepared by the gelation route. Addition of pre-condensed silica particles improved mechanical properties of composite materials compared to silica derived from TEOS. The development of novel methods of separating silk fractions will improve the availability of these fractions for future research and give a robust base for further studies in areas such as dental materials, biomaterials, biochemistry and biotechnology. Natural silk fractions and inorganic composites have a large potential for future applications in industry and research however a lot more research is required for their detailed characterisation and their interaction studies within the biological environment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available