What is the common thread that could possibly link denim jeans, cancer and pesticides? None is evident. Yet when South African chemist Tebello Nyokong describes her fascinating research, the link that emerges is light. Nyokong, a specialist in nanochemistry, loves laser, and is using it in ways that could have a revolutionary impact on medicine and the environment.

A RHODES University scientist's ground breaking work in harnessing light for cancer therapy has won her a United Nations award worth almost R1- million. Named on Monday by the UN Educational, Scientific and Cultural Organisation (Unesco) as one of the world's top five "Exceptional Women Scientists", Professor Tebello Nyokong said winning the award was "just like getting a Nobel Prize". She was also recognised for her work regarding environmental cleanups. Nyokong, 57, grew up herding sheep in Lesotho and was unable to afford shoes. She now works in Rhodes University's chemistry department. She won the award for the Africa and Arab states category on World Science Day, which took place on Monday.

A passion for light drove Professor Tebello Nyokong of Rhodes University into her photodynamic therapy research, harnessing light for cancer therapy and environmental clean-up using special dyes. And with this groundbreaking work she won the Africa-Arab State 2009 L'Oreal UNESCO Award for Women in Science.

The Rhodes University professor of Medicinal Chemistry and Nanotechnology, Tebello Nyokong, says the Award for her Scientific Achievements by the International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM) is an honour, especially since it is awarded in memory of the centenary of the first Nobel Prize in Chemistry awarded to a woman: Marie Curie.

What is the common thread running through denim jeans, cancer and pesticides? None springs to mind, yet when chemist Tebello Nyokong describes her fascinating research, a link begins to emerge: light. A specialist in nanochemistry, Nyokong is using laser in ways that could revolutionize not only the diagnosis and treatment of cancer but also water purification. Born in Lesotho, Tebello Nyokong is Professor of Medicinal Chemistry and Nanotechnology at Rhodes University in South Africa and Director of the Nanotechnology Innovation Centre for Sensors (Mintek). In 2009, she was one of the five Laureates of the 2009 L’Oreal–UNESCO Awards for Women in Science.

Helen Grange profiles four women who've fearlessly taken on the complex predominantly male-dominated field of science.