The light fantastic

For years scientists have been researching and developing methods to treat cancer. Surgery, radiation, chemotherapy and immuno-therapy are the primary means of treating the disease but new methods of improving existing methods are being discovered.

Photodynamic therapy (PDT) is a relatively new approach to treating cancer that is currently being researched by scientists worldwide. This method of treatment combines the use of a red laser light and dye to kill cancerous cells in the body.
‘The dye is injected into the patient and it is accumulated preferentially in the cancer cells,” said Tebello Nyokong, a professor with the department of chemistry at Rhodes University in Grahamstown, who has spent more than 15 years combining her knowledge of chemistry with her passion for light to achieve a greater good. The red laser light is then shone on the cells containing the dye. The dye harnesses the light, transfers it to oxygen and in turn kills the cancer cells, said Nyokong.

At the Rhodes chemistry department, Nyokong and her team are in the process of developing dyes that will absorb more light.

The behaviour of the dyes in the presence of the laser light is also an area the team is focusing on. ‘Our molecules are meant to be more efficient and absorb more light.”

The dyes’ structure is similar to that used in blue jeans and ink in ballpoint pens, but have been modified for cancer treatment. The problem with the current dye is that it stays in the patient’s body for a long time and, as a result, they have to stay out of direct light. During treatment, some of the dye may be located in healthy cells surrounding the cancerous cells, resulting in the patient being sensitive to light. In some cases it stays in the patient’s body for a whole month.

This all depends on the type of cancer being treated, the patient and how much dye has been used during treatment. ‘We are trying to get our dye to be excreted faster.”

Nyokong and her team work in partnership with the Organic Intermediates and Dyes Institute in Russia. ‘We’ve been working together for about 10 years. They are already testing this treatment on patients. They test with slightly different molecules. You get different molecules to treat different cancers.”

The National Research Foundation and the National Laser Centre in Pretoria fund the research project. This method can be used to treat any cancer. ‘It all depends on whether the light will be able to reach the cancerous area,” said Nyokong.

Once approved, this method of treating cancer will eliminate side effects such as thinning of hair associated with chemotherapy.

On Friday March 18, Professor Tebello Nyokong will be presenting, Making Red Light Work on Cancer, at 3.30pm