Between 5 and 10% of bone fractures fail to heal completely, resulting in debilitating conditions that have a significant impact upon patients’ quality of life and represent a major financial burden for healthcare services. Existing treatments are highly invasive and rely on the immobilisation of the fracture site. Drugs to promote fracture healing do exist, but are not yet in clinical use due to the risk of off-target effects.

We are working with the Department of Bioengineering at Southampton University and the London School of Pharmacy to develop ultrasound responsive nanodroplets for the targeted delivery of osteogenic compounds.

In previous work we have demonstrated the feasibility of generating drug-loaded nanodroplets and that these can be used for delivery in vitro at moderate ultrasound intensities. Given the potentially high attenuation of ultrasound at a fracture site, however, it is important to minimise the acoustic pressures and/or pulse lengths required for delivery. We have shown that nanodropletvaporization can be achieved with exposure conditions that are not substantially higher than those used for therapeutic applications of microbubbles.

Transmission electron micrograph of perfluorocarbon nanodroplets

Alleviating Hypoxia in Rheumatoid Arthritis

As part of our work on microbubble optimisation, we have developed a technique for stably encapsulating oxygen within microbubbles. The oxygen-loaded formulations have been shown to promote the action of sonodynamic therapy drugs for cancer treatment by temporarily raising oxygen levels within tumours. We have shown that a similar effect can be produced by a nanoscale formulation that can be administered in the form of a drink, avoiding the need for intravenous injection. This formulation has been shown to produce an increase in athletic performance in healthy human volunteers and is now being trialled as a means of mediating the inflammatory response in rheumatoid arthritis.