Novel Electrospun Scaffolds for Bone Repair in Osteoporotic Patients

Osteoporosis is a chronic illness that affects an estimated 75 million people worldwide. The risk of fracture in osteoporotic patients is greatly increased; there were an estimated 9 million osteoporotic fractures in 2000. Bone graft substitutes are commonly used in orthopaedic surgery as bone fillers and to augment fracture healing. There are currently no commercially available bone graft substitute materials specifically designed for sufferers of osteoporosis. Bisphosphonates are a group of drugs taken orally by osteoporotic patients to improve general bone mass. Local administration of a drug mimic at a fracture site could allow faster integration of an implant and consequently reduce the risk of re-fracture. We have developed a biodegradable polymeric scaffold which incorporates a moiety found in bisphosphonates; polycaprolactone nanofibres have been functionalised with this drug mimic. Random polycaprolactone fibres have been collected on a grounded collector plate and then functionalised with the novel drug mimic. This structure has been moulded into 3-dimensional scaffold spheres. The 3D scaffolds have been characterised both chemically and physically; cellular interactions using bone forming cells, osteoblasts, have also been investigated. Osteoblasts attach and proliferate on the scaffold and have demonstrated enhanced function such as, an increase in the rate of mineralisation and collagen production when compared to polycaprolactone nanofibres alone. These properties are desirable in the design of bone graft substitutes for osteoporotic patients. Further cellular interactions using bone resorbing cells, osteoclasts, will be investigated.