KemetLeadsTebello Nyokong
A dye that does nothing in the dark, and then kills only what the light reaches.
The rise
Born in Maseru on 20 October 1951 and sent to her grandparents in the Lesotho mountains, she spent one day at school and the next with the family's sheep. She took her degree at the National University of Lesotho, a master's at McMaster and a doctorate at Western Ontario in 1987, and built her career at Rhodes University.
What they did
Phthalocyanines are ring-shaped dyes, inert until light hits them. Bound to nanoparticles that gather in a tumour and lit through a fibre, they release forms of oxygen that destroy the cells around them and nothing else — a cancer treatment without chemotherapy's systemic damage. She holds a national research chair and directs Rhodes's Institute for Nanotechnology Innovation.
The full picture
Photodynamic therapy using her compounds is still pre-clinical, not routine treatment. In a 2021 Nature Materials paper she and two colleagues set out why: African states pay salaries and buildings, foreign partners pay for the research itself, and little links results to products. No substantiated controversy attaches to her.
Why it matters
One day of school, one day with the sheep, then a research chair: the biography is itself the argument about wasted talent. What she does with it — a laboratory that trains Black chemists — is the rest of it.
“Many students in Africa have excellent theoretical scientific knowledge, but lack the tools for research. It is a travesty.”