Prof Eleanor Stride uses microscopic bubbles to deliver drugs and medicines to specific parts of the body. As the bubbles spread throughout the bloodstream, targeted ultrasound is used to burst them and release them at the exact point required. Interviewed by fellow University of Oxford academic Prof Denis Noble in her office at the Institute of Biomedical Engineering, Prof Stride explains the process which is about to start clinical trials and may one day be a commonplace method of targeted drug delivery.