Atmospheric Pressure Plasma Surface Engineering of Biomaterials for Biomedical Applications

Abstract

Three-dimensional (3D) bioprinting enables the creation of biological constructs closely mimicking the architecture of natural tissues and organs. Synthetic polymers, widely used as support materials in 3D bioprinting, often lack bioactivity and also face challenges in achieving strong interfacial adhesion with hydrogels. Conventional approaches for biofunctionalising synthetic polymers through covalent attachment of biomolecules and improving hydrogel adhesion rely on multi-step wet chemical processes with restricted patterning capabilities, making them incompatible with current 3D bioprinting frameworks. Atmospheric pressure plasma jet (APPJ) technology offers a dry, reagent-free alternative, eliminating the limitations of wet chemical processes. Therefore, an in-situ surface biofunctionalisation can be achieved by realising APPJ as an additional tool in biofabrication.

This thesis focuses on APPJ technology in surface biofunctionalisation, enabling the generation and controlled distribution of reactive and non-reactive oxygen-containing functional groups (OFGs) on substrates to create conjugation sites for covalent immobilisation of biomolecules. This approach facilitated the attachment of hydrogel monomers on diverse polymeric substrates, with the density of attached monomers tailored through modulation of charge-charge interactions. Building upon these findings, hybrid solid-hydrogel constructs were developed with enhanced hydrogel stability and interfacial adhesion employing an evaporation-induced enhanced concentration strategy. In vitro cell studies validated the biocompatibility of biofunctionalised constructs.

The results of this thesis highlight APPJ as an advanced biofunctionalisation tool, particularly valuable for applications like 3D bioprinting. By integrating APPJ technology with 3D bioprinter systems, future biofabrication processes could produce functionalised constructs tailored to diverse biomedical applications, tissue engineering, and beyond.