A new drug-delivery device developed at the University of California, Irvine, promises to unlock the potential of photosensitive chemicals to kill drug-resistant infections and potentially cancerous tumours.
Photosensitive chemicals are molecules that release single oxygen atoms and chemical radicals when illuminated, and can rip apart and destroy bacteria.
Yet photosensitive chemicals are not approved for use in the US, and used relatively rarely in Europe. This is because they are highly toxic and difficult to activate beneath the skin, since light only penetrates a few millimetres into the body. Although several have therapeutic potential, they are too toxic for human use by injection.
The researchers, led by Peter Rentzepis, a professor of chemistry at University of California, Irvine, solved this problem by developing a device that can deliver very small amounts of photosensitive chemicals to internal organs with pinpoint accuracy.
The device consists of a CCD imager that is illuminated by an LED through an optical fibre to enable a physician to guide it to the infection. Once the physician positions the device, the same light source shines with greater intensity to activate chemicals delivered through a hollow tube connected to a syringe. Pulling the syringe backwards creates a vacuum that sucks up any remaining chemical after the procedure.
’We can insert the instrument through the nose, bowels, mouth, or almost any opening and direct it where we want,’ said Rentzepis. ’It lets us deliver very small amounts of these chemicals right to an infection or tumour, then remove them before they damage healthy cells.’
The researchers now plan to test the device on animals.