A new way to deliver cancer drugs using gas bubbles and sound waves is to be developed at the University of Leeds. The project will enable highly toxic drugs to be delivered in small doses directly to tumours, where their toxicity can safely be put to good use. If successful, the technique could easily be adapted for other diseases.
The project brings together engineers, physicists, chemists and cancer specialists from across the University to work on the new technique. The research will use existing chemotherapy drugs to gain initial proof of concept before adapting the delivery mechanism for use with novel therapeutics being developed at the University to treat colorectal cancer.
Tiny gas-filled bubbles just a 1000nth of a millimetre across are already used in medicine to provide a clearer image on ultrasound scanners, because, when they are injected into the bloodstream, they reflect a stronger signal than the surrounding tissue. However, certain ultrasound signals will burst the bubbles and it is this phenomenon that the researchers plan to exploit as a clever cancer treatment.
The researchers will attach the drug to microbubbles, along with antibodies that are attracted to the tumour to make the bubbles congregate at the tumour site. Ultrasound will then be applied to the site at the correct frequency, and when the bubbles burst a manageable but effective dose of the drug will be released. An added benefit is that ultrasound can also temporarily rupture cell membranes, helping to get the drug into the cells where it can be most effective.
Lead researcher Professor Stephen Evans says: "A number of research teams are looking at possible uses for microbubbles, but with the breadth of expertise available at Leeds we're in a good position to make a breakthrough. For the technique to be a viable clinical and commercial option, we not only need to find a reliable way to attach the drugs and antibodies, we also need to be able to manufacture the bubbles in sufficient numbers, of the right size and with consistent properties."
Working on the ultrasound side of the project is Dr Steven Freear from the University's Faculty of Engineering. He is looking at how specially coded ultrasound waves interact with the microbubbles generated by Professor Evans' team. The aim is to control the delivery of therapeutic drugs to specific localised sites and encourage their uptake within cells.
"The ultrasound wave makes the bubbles resonate, vibrate and finally burst. By changing how we code the electrical excitation signal, we can image and verify how many bubbles are at the site to ensure we administer the right drug dose before we burst them." explains Dr Freear. "This means we can use ultrasound, not only to detect and image the microbubbles, but critically to rupture them, delivering the drug payload in a controlled way."