Investigation of handheld and multi-needle-coaxial electrohydrodynamic devices for biomedical applications

The electrohydrodynamic (EHD) technique has recently been the subject of much research due to its ability to process a wide range of materials into monodispersed micro/nano-sized products. Recent developments in the technology allow this process to be portable and allow the incorporation of multiple layers in the final product which further increases the potential applications of this technique. This work explores a modular EHD needle design as a handheld and multineedle format for wound dressing and drug delivery applications respectively. The first part of this work investigates the effects of the electrode and collector positioning on the products generated by EHD processing. The electric field and flight times measured indirectly were found to affect particles and fibres differently. Once this was established, a mobile unit was constructed and assessed in its ability to generate fibrous wound dressings in situ. The device was able to direct fibre deposition with great accuracy and ease of use. The dressings were electrostatically attracted to the skin and adhered well due to electrostatic forces. An additional application of the multi-needle device is in the manufacturing of drug delivery products. Multi-needle devices were used to produce multi-layered capsules containing PLGA-chitosan-PLGA for potential anti-cancer therapy. This research demonstrates the potential of the modular needle device to produce products with real world biomedical applications. By incorporating the multi-needle device into the handheld format, this gives the potential of creating layered structures potentially incorporating multiple active agents on demand which can be directed towards a site of injury.