Manufacturing bio functional PEEK implants by 3D printing and surface functionalisation with bioactive peptides

Surgery to remove cancer in the head and neck regions can result in severe tissue defects that cannot regenerate spontaneously. Craniofacial implants can help addressing severe soft and hard tissue defects in the skull and face by substituting missing hard tissues and providing a framework for attachment of remaining soft tissues. The success of such implants critically depends from their geometry, surface micro topography and ability to allow cell adhesion, proliferation and functions.

This project aims to address important bottlenecks in the fabrication and bio-functionalisation of PEEK implants aiming to achieve higher clinical efficacy.

PEEK is an emerging biomaterial for the fabrication of bespoke implants for craniofacial reconstruction. PEEK offers several advantages in comparison to titanium, the current gold standard. PEEK is transparent to X ray and NMR and has mechanical properties similar to bone. Nonetheless PEEK is bio inert and thus does not allow cell adhesion and bio-integration. PEEK implants are therefore often subject to fibrous encapsulation and they are clinically hypo functional. Recently, cell-instructive synthetic oligopeptides have been developed and have demonstrated excellent ability to drive differential cell functions (dependently from their primary sequence) in vitro and in vivo. Functionalisation of PEEK with such molecules has not been attempted so far.

We will employ digital 3D technologies (CAD/CAM) to design bespoke and patient specific implants and use recently developed PEEK 3D printers for their manufacture. We will evaluate printability of different geometries and internal implant geometry (fill patterns) in relation to mechanical properties of the final object.

In parallel, we will perform experiments to modify the surface topography of 3D printed samples and to enhance their bioactive properties. We will culture Endothelial cells and osteoblasts on modified PEEK surfaces to evaluate ability to induce angiogenesis and osteogenesis.

Person specification
The proposed project is novel and sufficiently ambitious for a motivated PhD wishing to work in biomaterial research and addressing both basic aspects of craniofacial implants fabrication and functionalisation as well as clinical considerations for their success.

Research training
We will employ APTES chemistry to allow covalent binding of synthetic oligopeptides able to promote adhesion of endothelial cells and osteoblasts and to promote their functions (angio/osteogenesis). To assess the performance of these functionalisation we will employ in vitro assays utilising primary endothelial cells and osteoblasts and assess their functions by immunofluorescence followed by high resolution microscopy, functional assays and gene expression analysis (qRT-PCR).