Electrospinning of polymers
The electro spinning process is of great utility in the manufacture of non-woven fabrics for a variety of applications including tissue engineering. A machine has been constructed capable of electrostatically spinning (electro spinning) a wide range of polymer solutions for the production of nano and micrometer diameter polymer fibres and fibrous non-wovens. The key role of these scaffolds in the research is in the making of tissue engineered scaffolds. Methods have been developed to allow control over the fibre topography enabling the production of fibrous polystyrene (PS) and poly(l-lactide) (PLLA) scaffolds within which skin cells can proliferate and self-organise. A polystyrene scaffold, without cell signalling chemistry, was made by electro spinning and used for coculture of fibroblasts, keratinocytes and endothelial cells. In the absence of growth serum the single cell cultures did not thrive, but together they did not need growth serum to populate the 3-D structure. When cultured at an air-water interface native spatial organisation was observed, demonstrating that not only does co-culture allow cells to proliferate without serum but also spontaneously self organise into the epidermal/dermal structure. Control over the fibre surface has also been achieved whereby electro spinning in a variable humidity environment alters the porosity of the fibre surface. The benefits of this surface control have been investigated in terms of the fibre's efficacy at drug delivery. Rates of delivery of a water soluble drug encapsulated within PLLA fibres with modified surface morphologies were monitored. It was shown that the surface pores were insufficiently large to cause a noticeable increase in drug delivery rates compared with totally smooth fibres. A novel electrospinning technique has been introduced and trialled whereby aligned micro and nanofibres of a range of polymers have been produced. This method represents a breakthrough technology in electrospinning where non-woven products are usually obtained.