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Title: Electrospun poly(caprolactone) and strontium-substituted bioactive glass for bone tissue engineering
Author: Santocildes Romero, Martin Eduardo
ISNI:       0000 0004 5357 880X
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2014
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Electrospinning is a technique which has been widely studied to fabricate fibrous polymeric membranes. More recent work has demonstrated the preparation of composite fibres by incorporation of ceramic or glass particles in the spinning process. However, the incorporation of strontium-substituted bioactive glasses (Sr-BGs) into electrospun membranes has not yet been studied with detail. This is perhaps surprising, as Sr-BGs have been reported to exhibit superior osteogenic activity compared to conventional bioactive glasses. Therefore, the aim of this project was to fabricate electrospun composite materials combining poly(caprolactone) (PCL) and Sr-BG particles, and to study their potential use as scaffolds for bone tissue engineering. Here, three Sr-BGs in which calcium was substituted by strontium in molar proportions of 0, 50 and 100% were prepared and characterised. Glass particles with sizes < 45 μm were prepared by milling and sieving, and added to PCL solutions before electrospinning. The resulting composite materials were then examined using scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), and by performing solubility and cytotoxicity studies. Two methods to add Sr-BG particles to the surface of the fibres were also investigated. The effect of Sr-BG dissolution on mesenchymal stromal cells (MSCs) was studied by assessing cytotoxicity and the expression of six genes associated with osteoblastic differentiation. Strontium substitution resulted in a reduction of glass transition temperature, increased density and increased solubility of the glasses. EDS confirmed the presence of Sr-BG particles within the electrospun fibres. Solubility studies suggested an accelerated degradation of PCL due to Sr-BG dissolution in the composite fibres, with an apparent effect on medium pH. All the materials generally presented good levels of in vitro biocompatibility, although the addition of particles to the surface of the fibres increased their apparent cytotoxicity in some cases. Sr-BG dissolution was associated with an up-regulation of genes involved in the process of osteoblastic differentiation. It was concluded that Sr-BGs may indeed enhance osteogenic differentiation in MSC populations, and electrospun PCL/Sr-BG showed great potential for use as a versatile medical device or scaffold for bone tissue regeneration.
Supervisor: Miller, Cheryl A. ; Hatton, Paul V. ; Reaney, Ian M. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available