Functionalised Polymer Fibres for Orthopaedic Interfacial Tissue Engineering and Other Biomedical Applications

摘要

Tissue engineering is a promising approach for the regeneration of a variety of human tissues, where traditional surgical repairs produce inadequate results or appropriate transplant material is in scarce supply. In orthopaedic tissue engineering, the regeneration of the bone/soft tissue interface is of special interest. However, this requires the creation of biomaterial scaffolds with controlled gradients of biochemical cues, in addition to mimicking the microstructure of the natural tissue. For this purpose, a scheme for the covalent immobilisation of biomolecule gradients on aligned synthetic nanofibre scaffolds created via electrospinning was devised. Surface-initiated atom transfer radical polymerisation allows for the controlled growth of a polymer brush containing reactive functional groups on the scaffold surface, specifically poly (glycidyl methacrylate) (PGMA), which contains epoxy groups that can conjugate to biomolecules via nucleophiles such as amines or thiols.udA PGMA-based biomolecule attachment scheme in a 2D model system was optimised. Creating a brush with a larger inter-chain spacing (by the replacement of a fraction of the ATRP initiator with an inactive molecule), as well as improving its water-swellability by incorporation of a water-soluble monomer (hydroxyethyl methacrylate, HEMA), were shown to increase the amount of peptide that could be bound to the polymer surface. Initial results indicate that this system can be used to create covalently immobilised gradients of biomolecules on aligned electrospun scaffolds.udThe versatility of the ATRP-based functionalistion approach was further demonstrated by creation of brushes of Poly (2-Methacryloyloxyethyl phosphorylcholine) (PMPC) on electrospun polymer fibres. Due to PMPC’s excellent haemocompatibility, these materials show great promise in vascular tissue engineering.