Bubbles for biofilm: acoustic stimulation for drug delivery in fracture repair

Bone fractures and their associated complications are a major societal problem that is set to get significantly worse as our population ages. Delayed bone healing and extended rehabilitation contribute to the 39 billion per year cost of bone injuries to the European economy, and approximately 150,000 wrist, vertebral and hip fractures cost the UK £2.1 billion annually. A proportion of bone fractures fail to heal appropriately with current clinical interventions, which include mechanical fixation or, more rarely, biomaterials and/or bioactive agents. New therapies are therefore urgently required. As yet, there is no clinically approved, systemic therapy for bone fracture.
We are developing such an approach. In preliminary work, we have found that nanoparticles (NPs) of known size accumulate at injury sites during specific windows post-fracture. We have used this approach to deliver therapeutic molecules to the injury site selectively at different phases of fracture healing without disrupting the healing tissue, the integrity of which is often critical to satisfactory outcomes (Figure 1). Aside from enabling the passive release of drugs at fracture sites, these observations now provide the exciting opportunity to remotely and actively control drug release and tissue stimulation in bone repair.