title: Electrostatic spinning of scaffolds for tissue engineering applications
Creators: name: Dawn. Andrews, Kirstie
Publisher: name: University of Liverpool Repository
Year: 2023

description: The field of tissue engineering is constantly seeking fabrication techniques for the optimum, application-specific production of scaffolds suitable for generating functioning cellular structures. The electrostatic spinning technique was investigated as such a technique. The aims of this research were to establish the potential of this technique with regard to: the ability to produce a range of reproducible scaffolds with a variety of structures and properties, related to the original fabrication conditions; the suitability of the produced scaffolds for cell-seeding and their potential to induce varying cellular behaviour; the ability to produce scaffolds with controlled variable properties; the potential to alter the scaffolds during or after production, inadvertently or through deliberate further modification; the ability of the modified scaffolds to alter the cellular behaviour. A range of 12.5% Tecoflex® polyurethane electrostatically spun scaffolds was produced,t hrought he systematicv ariation of the spinningp arametersT. he scaffold inter-fibre separation and fibre diameters were characterized using SEM. The scaffolds were seeded with 5x 104 L929 and human embryonic lung fibroblasts and cultured for 1 day, 1,4,8 and 12 weeks. Cell coverage, number, spreading, orientation and cytoskeletal involvement were investigated using SEM, image analysis and confocal microscopy. Cellular matrix and adhesion molecules were examined by immunostaining for collagen I, elastin, CD54 and CD106. Scaffold properties of Young's Modulus, surface roughness, contact angle and porosity were determined, using tensile testing, AFM, DCA and mercury porosimetry, and related to the original scaffold structures. Scaffold modification through scaffold sterilisation, ageing, surface modification with RGD sequences and the addition of metallic particulate to the spinning solution was tested. The resultant effect on the inter-fibre separation, fibre diameter and surface roughness was examined using SEM andA FM, andt he subsequenetf fectso n the cell coveragein vestigated. The electrostatic spinning technique was capable of fabricating fibrous scaffolds, with variable inter-fibre separation and fibre diameter. The alteration of the spinning parameters changed the mechanisms of spray jet manipulation around the electrostatic zone and fibre deposition, as did temperature, relative humidity and the mandrel coating. Scaffold thickness was varied by the flow rate and the duration of the spinning process. The scaffolds were capable of supporting cellular growth and adhesion, with significant differences present between scaffolds and cell types. Cell coverage, number, spreading, orientation and cytoskeletal involvement were altered between scaffolds through differences in the cellular growth methodologies. Scaffolds had different properties, showing some correlation to scaffold structure. Cell matrix anda dhesionm oleculesw ereu pregulateda crosst he scaffolds. The scaffolds were modified, with the structure and surface being altered, producing varying cellular results, dependent on the modification technique. It was feasible to add metallic particulate into the scaffolds during production. The electrostatic spinning technique showed potential for the use in the field of tissue engineering, with the capability of developing optimum, application-specific scaffolds.