This project is funded by the European Research Council. The work is for an exploratory study into a radical new approach to the problem of orthopaedic implant loosening. Such loosening commonly occurs because the joint between the implant and the surrounding bone is insufficiently strong and durable. It is a serious problem both for implants cemented to the bone and for those dependent on bone in-growth into a rough/porous implant surface. In the latter case, the main problem is commonly that bone in-growth is insufficiently rapid or deep for a strong bond to be established. The idea proposed in this work is that the implant should have a highly porous surface layer, made by bonding ferromagnetic fibres together, into which bone tissue growth would occur. During the post-operative period, application of a magnetic field will cause the fibre network to deform elastically, as individual fibres tend to align with the field. This will impose strains on the bone tissue as it grows into the fibre network. Such mechanical deformation is known to be highly beneficial in promoting bone growth, providing the associated strain lies in a certain range (~0.1%). Preliminary work, involving both model development and experimental studies on the effect of magnetic fields on fibre networks, has suggested that beneficial therapeutic effects can be induced using field strengths no greater than those already employed for diagnostic purposes.
A highly inter-disciplinary programme is planned, encompassing processing, network architecture characterisation, magneto-mechanical response investigations, various modelling activities and systematic in vitro experimentation to establish whether magneto-mechanical actuation of Ferromagnetic Fibre Networks shows promise as a new therapeutic approach to improve implant longevity.
DEVELOPMENT OF A BIOREACTOR SYSTEM FOR TISSUE ENGINEERING
Traditionally, optimised 2-dimensional surfaces have been used for growing cells in vitro. However, cellular functions of living tissues are missed by such cultures. To mimic the functions of living tissue, 3-dimensional (3D) cultures are needed. Such cultures bridge the gap between cell culture and live tissue and thus allow investigations of the real interactions between cells and novel biomaterials. Also, such culture would enable the production of cell-seeded matrices in vitro that can be used to promote tissue repair. Producing tissue in culture requires not only a suitable 3D scaffold but also the ability to control nutrient and gas exchange, as observed in the body, along with mechanical stimulation. This has led to the development of bioreactors. Bioreactors provide the appropriate culture environment to grow three-dimensional tissue using biologically relevant scaffolds. They can grow, modulate and preserve tissue growth, especially when applying suitable mechanical stimuli such as shear or perfusion. This project is being carried out in close collaboration with Dr Roger Brooks (Division of Trauma & Orthopaedic Surgery, Addenbrooke’s Hospital).
COLLAGEN-BASED VASCULAR NETWORKS FOR TISSUE ENGINEERING
One of the primary objectives of tissue engineering is the in vitro generation of synthetic tissues and organs. However an unsolved problem exists concerning vascular network generation, preventing the formation of large tissues and organs. In this project, we use collagen gels with various channel-forming techniques to create vascularized tissue, working towards solutions to this interdisciplinary problem. This project is being carried out in close collaboration with Dr Roger Brooks (Division of Trauma & Orthopaedic Surgery, Addenbrooke’s Hospital).
- Development of a Bioreactor System for Tissue Engineering
- Extraction of Fibre Network Architecture / FE Modeling
- Magneto-Mechanical Characterisation of Fibre Network Materials
- Biological Characterisation