Target practice

A research grant for £2m to aid the development of pioneering drug delivery treatment for cancer and gene therapy has been awarded to the universities of Dundee and St Andrews.

The announcement follows preliminary research undertaken over the past year. The universities achieved a breakthrough in 2005 in understanding how cancer cells can be targeted and destroyed by a single pulse of ultrasound energy using a ‘sniper rifle’ approach.

Dr Paul Campbell at Dundee‘s division of electronic engineering and physics explained that microbubbles, which measure about three microns, can be injected intravenously to boost ultrasound signals. When ultrasound is applied to microbubbles they are disrupted, causing small perforations in the target cells, which release the drugs and genes that are contained in their encapsulating layer.


Medical potential

Depending on the ultrasound intensity, these effects can be temporary and the cell will re-seal itself, locking in the drug. But if the intensity is increased the cell can be killed outright. Hence it is useful for cancer treatment and one reason why the technique holds such potential for future medical applications.

‘It has been known for 20 years or so that when you apply ultrasound, somehow molecules from outside the cells can traverse the cell membrane and be incorporated into the cell,’ said Campbell. ‘We didn’t understand exactly how that happened. So we devised an experiment to observe this under a microscope with a fast imaging camera, capable of one million frames per second.’

The camera, on loan from Rutherford laboratories, is usually used to study the impact of bullets and other weaponry.

Campbell and Prof Kishan Dholakia are developing the techniques learned from their research to create tools they hope will revolutionise the delivery of genes, drugs and therapeutic molecules to single cells and tissue samples. Using the new technology, which employs ultrasonics and optics (Sonoptics), the teams aim to capitalise on this new understanding in a biological environment.

‘It is a tedious and painstaking process using in vitro fertilisation to enter products into cells,’ said Campbell ‘My colleagues and I thought, “why not automate the ultrasound and have a fast and efficient way to load any molecule into any cell via this combination of optics and ultrasound?”‘

To exploit this technology the teams aim to develop an automated bench-top device for laboratory use, which Campbell claims will be a world first in terms of precision and control.


Force of light

The basis of the technology involves an unexpected property of light that, when sharply focused, can exert a tangible force on microscopic objects. The light can act like a miniaturised hand, ‘grabbing’ tiny objects and moving them to other locations – a process termed ‘optical tweezing’.

‘Once we complete the four-year project we will deliver an automated bench-top apparatus where you can put any cell of any choice in, trap it in an array of tweezers and use it with ultrasound and hopefully get that controllable optic facility,’ he said.

Campbell said the main aim of the project is to revolutionise the activation and delivery of drugs, genes and therapeutic molecules into live biological materials.

Being able to deliver drugs to remote anatomical sites in a controlled and non-invasive way is an area of growing interest globally. In the US, drug delivery technology is worth an estimated $30bn.

Dundee and St Andrews have demonstrated business awareness by patenting their work with a view to spinning out the technology using the money from the grant.