An innovative drug delivery device, designed and developed long ago, promises to unleash the potential of photosensitive chemicals in eradicating drug-resistant infections and cancerous tumors.
Photosensitive chemicals are molecules that release individual oxygen atoms and other chemical radicals following their irradiation. These radicals are very chemically active and are capable of breaking down and destroying bacteria, explains scientist Peter Rentzepis, professor of chemistry at the University of California (Irvine).
Despite this, photosensitive chemicals are not approved for use in the US, and their use in Europe is relatively rare. This is in light of the fact that they are particularly toxic to the body and also because it is difficult to work them under the skin, since light radiation only penetrates a few millimeters into the inside of the body. Photosensitive chemicals also cause serious side effects, such as headaches, nausea, and sensitivity to light for about a month. They may also destroy healthy cells, in addition to bacteria.
Although some of them have medicinal potential, the radicals are too toxic to be injected into the human body. The researchers solved this problem by using a device based on an optical fiber capable of delivering tiny amounts of photosensitive chemicals to internal organs in an extremely precise manner.
The device consists of three components. The first is an imaging component similar to the devices present in digital cameras. This component enables the guidance of the device to the exact point of contamination. A flexible optical fiber with a diameter of 1 mm, connected to a powerful micrometric diode or a laser source, provides the light to the first component. From the moment the doctor places the device at the desired point, this light is also used for the action of the medicine through powerful and point radiation. The third component is a hollow tube connected to a medical syringe through which the medicine can be delivered to the point of infection.
The researchers also add to the system the chemical glycol, a thickening agent used in medical soaps, in order to prevent the drug from spreading to healthy cells. Pulling the syringe back creates a vacuum which sucks and removes all the chemical residues left at the end of the procedure. "We are able to insert the device through the nose, intestines, mouth and any other opening in the body, and direct it exactly to the point we want," explains the lead researcher. "This approach allows us to transfer tiny amounts of these chemicals exactly to the point where the infection or cancerous tumor is located, and to remove them before damage occurs to healthy cells," notes the researcher.
