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Leaders in Innovation

Honoring the Lives of NIHF Inductees Helen Free and Spencer Silver

At the National Inventors Hall of Fame® (NIHF), we have the distinct privilege of honoring some of the world’s most influential inventors: our NIHF Inductees. By highlighting their achievements in our K-12 STEM (science, technology, engineering and mathematics) education programs, stories on our blog, annual Induction Ceremony and NIHF Museum exhibitions, we honor our Inductees’ enduring legacies.


Please Join Us in Honoring the Lives of NIHF Inductees Helen Free and Spencer Silver

This year, we’re reflecting on the lives and accomplishments of two NIHF Inductees who have passed away: Helen Free and Spencer Silver. We invite you to read below and learn more about their meaningful contributions to our society.


Helen Free

Known as a pioneer in diagnostic chemistry, Helen Free’s research, in collaboration with her husband and fellow NIHF Inductee Alfred Free, led to the creation of convenient dip-and-read urine tests (marketed as Clinistix®), which advanced diabetes testing by detecting blood glucose. This test made it possible for millions of people to monitor their diabetes in a simple and convenient way. Today, the brand remains in use and is marketed as Ascensia Diabetes Care.

Following the success of Clinistix, Free and her husband developed additional urine tests used to accurately monitor pH levels, nitrates, ketones and bilirubin. By 1981, the two had developed Multistix®, a single urine test that included 10 different clinical tests on a single strip — further revolutionizing the science of diagnostic urine testing.

Free earned seven U.S. patents and was an active member of the American Cancer Society, the American Association of Clinical Chemistry, the American Association for the Advancement of Science, the American Society of Medical Technology and the American Chemical Society, of which she was the president in 1993. In 2009, she was awarded the National Medal of Technology and Innovation.

Her impact extends far beyond her professional accomplishments, and through the Al and Helen Free Foundation, a nonprofit organization created with her husband, their legacy continues to support the NIHF Children’s Endowment Fund, which provides scholarships for underserved children to attend NIHF education programs.

As her obituary reminded us, “in spite of all these leadership positions and awards, she was just as much known for her kindness, outreach, enthusiasm, and encouragement.”


Spencer Silver

In 1968, while working as a research chemist at 3M, Spencer Silver discovered an acrylic adhesive that had unique properties. It was formed out of tiny spheres that provided a high level of tack, but a low degree of adhesion. At first, many within the company could not picture a practical use but Silver was determined to find an application.

“I felt my adhesive was so obviously unique that I began to give seminars throughout 3M in the hope I would spark an idea among its product developers,” he recalled in an interview with the Financial Times in 2010.

Everything changed in 1974, when he met a chemical engineer at 3M who was looking to develop new products: NIHF Inductee Art Fry. Fry began thinking about how the paper bookmarks in his hymnal would often fall out when he sang with his church choir, and he started using Silver’s adhesive to prevent this from happening. The adhesive was gentle enough to prevent the pages from tearing, and the two realized that they had something special on their hands.

In 1980, 3M began selling Post-it® Notes nationally, and the product became a runaway success. Billions are now sold annually around the world. Discussing how popular the invention was with consumers, Silver noted “it was always a self-advertising product,” he said in an interview with CNN. “They would look at it, peel it off and play with it, and then go out and buy a pad for themselves.”

Silver’s legacy continues through The Spencer Silver Memorial Endowment Fund, established by his family, which provides scholarships for underserved children in Minnesota to attend Camp Invention®.


Learn More About Our World-Changing Inductees

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