UMN ME Researchers Shape the Future of Cryobiology in Prestigious Annual Review of Heat Transfer

Chapter 2: Mathematical Treatments of Ice Formation and Vitrification During Cryopreservation

UMN ME Authors:
 Chris Hogan – Department Head, James J. Ryan Professor
 Joseph Kangas – Research Faculty and Lecturer.
 
This chapter presents mathematical frameworks for modeling the complex biophysical processes of ice formation and vitrification in cryopreserved systems. Focused on small-scale biological samples such as cells and embryos, the models account for variables including cryoprotectant concentration, cooling rates, and thermal gradients. Through numerical simulations and theoretical analysis, the authors provide a foundational understanding of how to avoid damaging ice crystallization and promote successful vitrification. These insights directly support the design of safer and more predictable cryopreservation protocols in regenerative medicine and reproductive biology.

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Chapter 6: Enhanced Heat Transfer for Improved Ice-Free Cryopreservation

UMN ME Authors:
John Bischof – Distinguished McKnight University Professor
Zongqi Guo – Postdoctoral Researcher

This chapter introduces CryoMesh™, an innovative platform engineered to enable uniform and efficient thermal transport during vitrification of complex biological specimens. By improving heat transfer dynamics during both cooling and rewarming, CryoMesh™ helps maintain viability of tissue slices, pancreatic islets, and small organisms without the formation of damaging ice. The chapter explores the underlying physics, materials design, and experimental validation of the technology, positioning CryoMesh™ as a transformative tool in the pursuit of reliable, ice-free biopreservation.

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Chapter 8: Review of Bulk Cryopreservation Enabled by Nanowarming

UMN ME Authors:
John Bischof – Distinguished McKnight University Professor
Lakshya Gangwar, Zonghu Han, Onyinyechukwu Oziri – Postdoctoral Researchers
Srivasupradha Ramesh – Graduate Research Assistant
Michael Etheridge – Researcher 7

This chapter provides a comprehensive review of nanowarming, a technique that uses magnetically responsive nanoparticles and radiofrequency fields to rapidly and uniformly rewarm vitrified tissues and organs. Addressing one of cryopreservation’s greatest challenges—safe rewarming of large biological systems—the authors examine how nanowarming overcomes limitations of conventional heating methods. The chapter highlights successful applications in organ models and outlines the path toward scalable, clinically viable solutions for long-term organ storage.

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These contributions showcase the depth of talent and innovation in the Department of Mechanical Engineering at the University of Minnesota. From theoretical modeling to translational biomedical devices, ME faculty, researchers, and students continue to push boundaries in thermal science with real-world medical impact.