IU Alumni Invented Fluoride Toothpaste and DNA's Double Helix

The toothpaste in your bathroom and the DNA model in every biology textbook share an unexpected connection: they both came from Indiana University researchers.

Since the 1930s, IU faculty and alumni have been quietly solving problems that touch billions of lives. The university's Innovation and Commercialization Office has issued 1,340 patents in just the past 15 years, keeping pace with a legacy that started nearly a century ago.

Back in 1931, biochemist Rolla Harger invented the "drunkometer" while teaching at IU's School of Medicine. Suspects would breathe into a balloon containing a chemical solution that darkened based on alcohol concentration, working like a pH test strip. Harger patented his invention in 1936, just as Prohibition ended and drunk driving surged.

Years later, Harger trained Robert Borkenstein at IU, who went on to create the modern breathalyzer in 1954. The tools that help keep drunk drivers off roads today trace their roots to that IU laboratory.

The 1950s brought another everyday breakthrough. Faculty members Harry Day, Joseph Muhler, and William Nebergall developed fluoride toothpaste after Muhler discovered that stannous fluoride strengthened weakened tooth enamel. Proctor & Gamble bought the patent, and in 1955, Crest toothpaste arrived in stores worldwide.

The American Chemical Society recognized the achievement with a permanent plaque through its National Historic Chemical Landmark program in 2024. IU also commemorated the invention with a historical marker in 2020.

Around the same time, James Dewey Watson completed his doctorate in virus research at IU before heading off to tackle one of science's biggest mysteries. Working with Francis Crick in 1953, Watson discovered that DNA's building blocks link in definite pairs: adenine with thymine, guanine with cytosine.

Using X-ray diffraction pioneered by Rosalind Franklin, they determined DNA's famous double helix structure, explaining how genetic information copies itself. The discovery earned Watson and Crick the 1962 Nobel Prize for Physiology and Medicine.

The Ripple Effect

German physicist J. Hans D. Jensen, a former IU visiting professor, shared the 1963 Nobel Prize for Physics for proposing the shell nuclear model. His work revealed that protons and neutrons orbit an atom's nucleus in pairs, spinning on their own axes within shells.

Since atoms form the building blocks of everything in the universe, Jensen essentially helped reveal the structure of all matter. Three researchers working independently, including Jensen, finally answered questions physicists had been asking since the 1930s.

From preventing cavities to understanding the code of life itself, IU researchers have spent decades turning curiosity into solutions. As IU President Pamela Whitten said at the National Historic Chemical Landmark unveiling, it's about "translating research to impact countless lives."

The patents keep coming, and the discoveries continue.

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