Possible Applications of Directional Solidification Techniques in Cyobiology

  • I. Heschel
  • C. Lückge
  • M. Rödder
  • C. Garberding
  • G. Rau
Part of the A Cryogenic Engineering Conference Publication book series (ACRE, volume 41)


During freezing of cell suspensions, the cooling rate achieved generally varies markedly throughout the bulk sample. As the cooling rate strongly affects cell survival, this may lead to a variation of cell survival with position in the sample. To avoid these problems, in many basic investigations microscopic sample volumes are used. But even in this case effects like the undercooling of the aqueous samples occur that prevent the study of cells under well defined thermal conditions. Thus the directional solidification of microscopic biological samples according to the Bridgman-technique was introduced to cryobiology. This technique allows the highly defined freezing of small samples and the independent control of the two fundamental solidification parameters, ice front velocity, v, and temperature gradient, G. The cooling rate B is simply the product of the two parameters, v and G, and can easily be adjusted. Applications of the Bridgman-technique are the study of the crystallization morphology (e. g. measurement of the solute pile up and the breakdown time, dendrite spacings, tip radius, electrical potentials, etc.) and the study of the interactions between growing ice crystals and biological cells (e. g. intracellular ice formation, encapsulation or rejection of cells). But although the advantages are obvious for microscopic samples, the Bridgman-technique cannot be adapted to the cryopreservation of bulk systems. In this case an alternative approach, the directional solidification according to the power-down technique can be applied. The aqueous sample is enclosed between two blocks which provide the temperature control. After a constant temperature gradient is established between the two blocks both block temperatures are lowered simultaneously with identical cooling rates. The ice front then grows with a constant velocity from the cold to the warm block. Freezing simulations and experimental results show that the power-down technique offers a great potential for future studies. Possible applications are the cryopreservation of delicate cell types which require uniform cooling conditions (e. g. heart muscle cells, oocytes), basic investigations on the mechanisms of cell and tissue damage during freezing (cryosurgery), and the processing of frozen samples with a defined and uniform microstructure (morphology studies in bulk samples, improved freeze-drying protocols, and processing of biomaterials with defined pore sizes).


Cool Rate Directional Solidification Aqueous Sample Physiological Salt Solution Heart Muscle Cell 
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  1. 1.
    U. Hartmann, B. Nunner, Ch. Körber, G. Rau, Where should the cooling rate be determined in an extended freezing sample, Cryobiology 28:115–130 (1991).CrossRefGoogle Scholar
  2. 2.
    I. Heschel, F. Schneider, Ch. Körber, A numerical study of the cooling rate variation within cylindrical samples, Cryobiology 28: 586 (1991).Google Scholar
  3. 3.
    C. Lückge. “Thermal Events during Freezing of Biological Cell Suspensions and their Influence on Cell Survival”, diploma thesis, FH Aachen, Germany (1992).Google Scholar
  4. 4.
    A. Sputtek, G. Rau, Kryokonservierung von Humanerythrozyten mit Hydroxyethylsfärke (HES) — Teil 1: Verfahrensbeschreibung, Infusionstherapie 19: 269–275 (1992).Google Scholar
  5. 5.
    W. Kurz, D. J. Fisher. “Fundamentals of Solidification”, 3rd ed. Trans Tech Publications, Aedermannsdorf, Switzerland (1989).Google Scholar
  6. 6.
    Ch. Körber, S. Englich, P. Schwindke, M. W. Scheiwe, G. Rau, A. Hubel, E. G. Cravalho, Low temperature light microscopy and its application to study freezing in aqueous solutions and biological cell suspensions, J. Microscopy 141: 263–276 (1986).CrossRefGoogle Scholar
  7. 7.
    B. Rubinsky, M. Ikeda, A cryomicroscope using directional solidification for the controlled freezing of biomaterials, Cryobiology 22: 55–68 (1985)CrossRefGoogle Scholar
  8. 8.
    J. Beckmann, Ch. Körber, G. Rau, A. Hubel, E. G. Cravalho, Redefining cooling rate in terms of ice front velocity and thermal gradient: first evidence of relevance to freezing injury of lymphocytes, Cryobiology 27: 279–287 (1990)CrossRefGoogle Scholar
  9. 9.
    A. Hubel, E. G. Cravalho, B. Nunner, Ch. Körber, Survival of directionally solidified B-lymphoblasts under various crystal growth conditions, Cryobiology 29: 183–198 (1992)CrossRefGoogle Scholar
  10. 10.
    B. Nunner, Ch. Körber, G. Rau, Characterization of the ice front morphology developing during the directional solidification of aqueous solutions, submitted to J. Crystal Growth Google Scholar
  11. 11.
    Ch. Körber, Phenomena at the advancing ice -liquid interface: solutes, particles and biological cells, Q. Rev. Biophys. 21: 229–298 (1988)CrossRefGoogle Scholar
  12. 12.
    B. Rubinsky, C. Y. Lee, J. Bastacky, G. Onik, The process of freezing and the mechanism of damage during hepatic cryosurgery, Cryobiology 27: 85–97 (1990)CrossRefGoogle Scholar
  13. 13.
    W. Kurz, P. R. Sahm, Gerichtet erstarrte eutektische Werkstoffe, in: “Reine und angewandte Metallkunde in Einzeldarstzellungen, Vol. 25”, W. Köster ed., Springer, Berlin (1975)Google Scholar
  14. 14.
    J. S. Erickson, C. P. Sullivan, F. L. Versnyder, Modern processing methods and investment casting of the superalloy family, in: “High-Temperature Materials in Gas Turbines”, P. R. Sahm and M. O. Speidel eds., Elsevier, Amsterdam (1974)Google Scholar
  15. 15.
    I. Heschel, M. Rödder, C. Lückge, B. Nunner, G. Rau, A power-down device for the directional solidification of macroscopic samples, Cryobiology 29: 767 (1992)Google Scholar

Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • I. Heschel
    • 1
  • C. Lückge
    • 1
  • M. Rödder
    • 1
  • C. Garberding
    • 1
  • G. Rau
    • 1
  1. 1.Helmholtz-Institute for Biomedical EngineeringAachen University of TechnologyAachenGermany

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