Robert L. Letsinger

Robert L. Letsinger, 92, a professor of chemistry emeritus at Northwestern University who played a critical role in developing DNA synthesis methods, died on May 26 at his Seattle home.

Born in Bloomfield, Ind., Letsinger earned a B.S. in chemistry in 1943 and a Ph.D. in organic chemistry in 1945, both from Massachusetts Institute of Technology. During World War II, he conducted research at MIT with the Rubber Reserve Corp., contributing to the development of a new method for preparing synthetic rubber.

In 1946, Letsinger became an instructor in the chemistry department at Northwestern, where he would remain for 50 years.

Letsinger conducted pioneering research focused on developing solid-phase methods for rapid and convenient synthesis of oligonucleotides using a range of internucleotide linkage chemistries developed in his lab. This work provided a foundation for new approaches to medical research.

He served on several medical advisory boards and was an HIV research consultant for Gilead Sciences. After retiring from teaching in 1991, he cofounded Nanosphere, a biotech firm specializing in the development of medical diagnostic tools.

Letsinger was elected to the National Academy of Sciences in 1986 and the American Academy of Arts & Sciences in 1988 and was an emeritus member of ACS, joining in 1944.

He received many awards, including the Humboldt U.S. Senior Scientist Award in 1988 and the B. F. Goodrich Collegiate Inventors Award in 1997.

Letsinger traveled extensively, both professionally and for pleasure. His family remembers him for his warmth and humor, his enthusiasm for greeting life’s challenges, and his ease in expressing gratitude.

He was predeceased by his wife, Dorothy; his daughter Rita; and a grandson. He is survived by his son, Reed; daughter Sue; two grandchildren; and three great-grandsons.