Investigation of single-needle and multi-needle electrohydrodynamic processes for the preparation of advanced bioproducts

• Main Author: Sofokleous, P. D.
• Published: University College London (University of London) 2014
• Subjects: 621
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631914

Polymeric products with micro/nano dimensions have attracted substantial interest in recent years and it has been shown that complex structures can be generated from solid and encapsulated particles/fibres. Although several techniques have been used to engineer these products their disadvantages such as high processing costs and the need for solvents and additives that are not fully biocompatible, lead to poor controllability and biological stability of the bioactive agents. In contrast, electrohydrodynamic (EHD) and co-axial EHD (CEHD) processes are simple and inexpensive techniques that can produce solid and multicomponent products on the nano/micro scale in a single step and under ambient conditions. The parameters affecting the formation of these products using the EHD process are well-known but on the other hand studies using the CEHD process are limited; hence the first objective of this work was to investigate the different physical and mechanical processing parameters affecting the encapsulated fibres produced by the CEHD process. The second objective of this study was to use a single needle EHD system to prepare and investigate the release of amoxicillin from electrospun polymeric fibrous wound dressing patches for wound healing and infection control. This work establishes a potential method of producing drug-loaded polymeric micro fibres with a controlled release behaviour that can be use in wound care industry. The third objective of this study was to improve the EHD and CEHD processes by designing and constructing an advance multi-needle assembly device where the needle height displacement between the needle tips could be controlled, which was then inserted in a portable handheld electrohydrodynamic spray gun. The spray gun was tested successfully for its ability to engineer solid and encapsulated products. The fourth and last objective was to investigate how the needle height displacement between their needle tips, in a two needle co-axial EHD assembly system, is affecting the production of encapsulated particles/fibres and the percentage number (n%) of the encapsulated products formed. By successfully achieving these objectives it was proved that there are still ways to improve the EHD and CEHD techniques in order to expand their use in many other technological and pharmaceutical fields.