Targeted drug delivery could be transformed by microbubble technology

Scientists have found a way to illuminate tiny bubbles which are used to track blood flow with medical imaging. In future such bubbles could also deliver targeted drugs in the body.

Until now, researchers have been unable to accurately study the flexibility of microbubble shells, which are injected into the bloodstream as an aid to ultrasound imaging. This lack of information meant that it was hard to predict exactly how the bubbles would behave under the ultrasound beams.

By adding a glowing molecule just beneath the outer shell of the bubble, researchers at Imperial College London and the University of Oxford were able to study the shells of bubbles in minute detail for the first time using a powerful microscope.

This allowed them to accurately map microbubble shells and determine how flexible they are and could lead to future applications for targeting drug delivery to specific areas that require treatment.

One of the lead researchers, Dr Marina Kuimova, from the Department of Chemistry at Imperial, says, ''The new technique can potentially have a big impact on our understanding of how microbubbles interact with living cells and each other in blood vessels.  We can now begin work on how to manipulate or manufacture microbubbles for use in medical treatments.''

In addition to tracking microbubbles' movements through the body, the researchers also demonstrated that addition of the certain molecules to the bubble shells makes them more stable. In the future, scientists could replace these molecules with drugs, so that the bubbles could deliver medicine in an efficient, targeted way.

Information about the properties and behaviours of microbubbles may also be used to improve how they are created so that bubbles can be designed for specific biomedical purposes, such as enhancing how they are used in ultrasound and for delivering drugs directly to where they are required in the body.

Dr Eleanor Stride, from the Department of Biomedical Engineering at Oxford, said: ''This valuable new method will enable us to understand how the microbubble manufacturing techniques we are developing affect the properties of the microbubbles and hence how we can optimise their response to ultrasound for both imaging and drug delivery applications."

The paper was the cover story in a recent edition of the journal Proceedings of the National Academy of Sciences (PNAS).

The research was funded by EPSRC and the UCL/Imperial kick start fund.