In 1998, University of Wisconsin-Madison researchers made waves in the worlds of biology and medicine, revealing they had five examples of human embryonic stem cells  — biological building blocks at the foundation of cellular development — successfully isolated and growing on laboratory dishes.

Visit the Madison-based stem cell bank WiCell today, and you’ll find a library of 1,364 different lines of stem cell cultures, an indicator of how far the field has come since that breakthrough 20 years ago.

Enter the secure room in WiCell’s home in University Research Park, and you’ll find five-foot-tall metal tanks, each storing 47,000 vials full of stem cells floating in a nutrient-rich liquid medium. Staff unseal the tanks, unleashing plumes of liquid nitrogen vapor, and place the vials in large R2-D2-like cylinders that ship to teams of scientists and pharmaceutical companies in Madison and around the globe for research projects, clinical trials and biotechnology products.

WiCell has made more than 7,000 shipments to 45 countries across six continents since its founding in 1999, according to its director Tenneille Ludwig. Thanks to the proliferation of stem cells and the training of researchers to work with them, two things that WiCell has helped enable, Ludwig said there have been about 13,000 academic papers on stem cells published over the past 19 years. Read the full story here.