TY - GEN
T1 - Biophysics of freezing of tissue equivalents
AU - Balasubramanian, Saravana Kumar
AU - Bischof, John
AU - Hubel, Allison
PY - 2005
Y1 - 2005
N2 - Understanding the biophysical processes which govern injury during freezing of a tissue equivalent (TE) is an important step in understanding and improving cryopreservation in these systems. TEs were formed by entrapping human dermal fibroblasts (HDFs) in collagen or in fibrin gel. Freezing studies were performed using a Linkam cryostage fitted to an optical microscope allowing observation of TE cooling under controlled rates between 5-130°C/min, Typically, freezing results in two biophysical processes inversely dependent on cooling rate: dehydration or intracellular ice formation (IIF). Both of these processes can be lethal to cells. In this study we have measured these biophysical processes and fit the behavior to models so as to extract parameters that govern water permeability, E Lp and L pg, and parameters that govern intracellular ice nucleation, Ωo and κo. Biophysical behavior was also found to depend on cell-cell and cell-matrix interactions. For example, HDFs in suspension show 55% IIF whereas HDFs in collagen and in fibrin TE 100% IIF at 130 C/min cooling rate. Further differences were noted and quantified by obtaining biophysical parameters for HDF cells in suspension vs. entrapped in collagen or fibrin gels.
AB - Understanding the biophysical processes which govern injury during freezing of a tissue equivalent (TE) is an important step in understanding and improving cryopreservation in these systems. TEs were formed by entrapping human dermal fibroblasts (HDFs) in collagen or in fibrin gel. Freezing studies were performed using a Linkam cryostage fitted to an optical microscope allowing observation of TE cooling under controlled rates between 5-130°C/min, Typically, freezing results in two biophysical processes inversely dependent on cooling rate: dehydration or intracellular ice formation (IIF). Both of these processes can be lethal to cells. In this study we have measured these biophysical processes and fit the behavior to models so as to extract parameters that govern water permeability, E Lp and L pg, and parameters that govern intracellular ice nucleation, Ωo and κo. Biophysical behavior was also found to depend on cell-cell and cell-matrix interactions. For example, HDFs in suspension show 55% IIF whereas HDFs in collagen and in fibrin TE 100% IIF at 130 C/min cooling rate. Further differences were noted and quantified by obtaining biophysical parameters for HDF cells in suspension vs. entrapped in collagen or fibrin gels.
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M3 - Conference contribution
AN - SCOPUS:33646571844
SN - 0974249211
SN - 9780974249216
T3 - Proceedings of the 2005 Summer Bioengineering Conference
SP - 1338
EP - 1339
BT - Proceedings of the 2005 Summer Bioengineering Conference, 2005 SBC
T2 - 2005 Summer Bioengineering Conference
Y2 - 22 June 2005 through 26 June 2005
ER -