Mostafa El-Sayed

Born

1933, Zifta, Egypt

Nationality

Egyptian-American

Field

Physical chemistry; spectroscopy; nanoscience

Known for

The El-Sayed rule; gold-nanoparticle research; U.S. National Medal of Science (2007)

Institutions

UCLA; Georgia Institute of Technology

From the Nile Delta to American laboratories

El-Sayed was born in Zifta, a town in Egypt's Nile Delta, and took his first degree at Ain Shams University in Cairo before moving to the United States for doctoral work at Florida State University. Postdoctoral positions at Harvard, Yale and Caltech followed, and in 1961 he joined the faculty of UCLA, where he spent more than three decades. In 1994 he moved to the Georgia Institute of Technology, holding the Julius Brown Chair and directing its Laser Dynamics Laboratory.

He was also, for close to a quarter of a century, editor-in-chief of the Journal of Physical Chemistry, one of the field's central publications — a role that placed him at the middle of his discipline's day-to-day life as well as its research front.

The El-Sayed rule

Published in the early 1960s, the rule that carries his name concerns intersystem crossing: the process by which an excited molecule switches between electronic states of different spin. El-Sayed showed that the switch happens far faster when it is accompanied by a change in the type of molecular orbital involved than when it is not. Stated compactly, that single observation explains why some molecules phosphoresce strongly and others barely at all.

The rule is still taught as a standard result in photochemistry and molecular spectroscopy, and it underlies practical decisions in designing dyes, sensors, light-emitting materials and photodynamic drugs.

Gold nanoparticles and cancer

From the 1990s onwards his laboratory became known for work on the optical behaviour of metal nanoparticles — how gold spheres and rods absorb and scatter light depending on their size and shape. That physics has a direct medical application: nanoparticles tuned to a particular wavelength and attached to targeting molecules can make cancer cells visible under a microscope, and can convert absorbed laser light into heat sharply enough to destroy them. Much of the applied work was carried out in collaboration with clinical researchers, including his son Ivan El-Sayed, a head and neck surgeon.

Recognition

El-Sayed was elected to the U.S. National Academy of Sciences and received the National Medal of Science, the United States' highest scientific honour, for the 2007 class — recognition covering both the fundamental spectroscopy of his early career and the nanoscience of his later one. He has also been a prominent advocate for scientific research and education in the Arab world.

Relation to the name

He writes his given name Mostafa, with an o: the standard Egyptian transcription, reflecting how the first vowel is actually pronounced in Egyptian Arabic. The reasoning is set out on the Mostafa spelling page, and the wider family of forms in the spellings guide.

Egypt has produced a long line of scientists and scholars carrying the name, a tradition that runs from Ottoman-era historians to modern universities — collected under scholars and scientists named Mustafa.

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