Ulster University has established a collaboration with leading universities in the USA and Ireland on a £1.5 million research project to revolutionise bone fracture healing in patients across the globe. Brian Meenan talks to OPN about the pioneering project.
Tell us a little about your background and education in the orthopaedic industry?
My academic background is in surface chemistry and its applications to advancing biomaterial science. In particular, my research group at Ulster has been studying the effects of bioactive calcium phosphate materials such as hydroxyapatite (HA) on bone and stem cell biology for over 15 years. It is the application of these systems as potential coatings on implant devices that has been the basis of our interactions with the orthopaedic industry and with clinicians.
Along with my colleagues Adrian Boyd and Patrick Lemoine, we are using physical deposition methods such as radio-frequency magnetron sputter deposition to modify the surfaces of orthopaedic metal alloys in a way that promotes their more rapid integration with bone tissue in vivo. Although such coating techniques are difficult to apply to joint replacement devices such as the femoral stem, they are ideal for providing thin bioactive coatings on pins and wires, where processes such as plasma spraying are less effective due to the need for surface roughening to induce a well-adhered surface layer.
Our recent work on sputter coating from substituted hydroxyapatite materials (i.e. replacing calcium ions in the HA lattice with strontium, zinc, magnesium or silver ions) provides the opportunity to further tune cell response to the implant surface in a way that reflects the maturity and pathology of the contacting tissue, as appropriate.
Could you tell us more about the magnesium-based orthopaedic implants and how they are able to be reabsorbed by the body after a fractured bone has healed?
The overall aim of this US–Ireland R&D centre-to-centre partnership collaboration is to develop bioresorbable orthopaedic implants made from novel high-strength, high-ductility magnesium and magnesium alloy systems that can replace the permanent metals/metal alloys usually used in applications ranging from thin wires to thicker pins, rods and elastic stable intramedullary nails (ESINs), as well as meshes for the treatment of complex bone fractures. We will use both existing high-purity magnesium systems and new magnesium alloys that are currently being developed by the National Science Foundation Engineering Research Centre (NSF-ERC) for Revolutionizing Metallic Biomaterials (RMB) using novel processing methods (patents pending).
In addition to using them in their inherent state, we are employing advanced surface modification and coating procedures developed at the Nanotechnology and Integrated BioEngineering Centre (NIBEC) at Ulster University to control key interfacial properties for the clinical applications concerned; we use bespoke, finite element models developed at the Science Foundation Ireland Centre for Research in Medical Devices (CÚRAM) at the National University of Ireland, Galway (NUIG) to provide the data to target multiple applications by varying bulk and surface properties.
How will your device help surgeons and benefit patients?
A severe bone fracture often requires surgery using metal pins, rods or plates to ensure it heals in the correct position. These implants are most commonly made from stainless steel or titanium and often need to be removed after a fracture has healed.
The novel magnesium-based orthopaedic device being developed by the collaborating universities w