2005 Fiscal Year Final Research Report Summary
Active Enhancement of Microscale Heat and Mass Transport in the Process of Cryopreservation and Establishment of the Method of Viability Assessment
| Project/Area Number |
14205033
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Thermal engineering
|
|---|
| Research Institution | Nihon University |
|---|
Principal Investigator |
TANASAWA Ichiro Nihon University, Dept.Mechanical Engineering, Visiting Researcher, 工学部, 客員研究員 (30013105)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OMATA Sadao Nihon University, Dept.Electrical Engineering and Electronics, Professor, 工学部, 教授 (90060186)
SHIRAKASHI Ryo University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (80292754)
|
|---|
| Project Period (FY) |
2002 – 2005
|
| Keywords | Biomedical Engineering / Cryopreservation of Biological Cell / Cryoprotective agent / Viability Assessment / Bio-heat and mass Transport / Active control of Mass Transport / Use of an Electric Field / Measurement of Tenderness |
|---|
| Research Abstract |
The fatal damage caused by ice crystals formed inside and/or outside the cells should be avoided to lead cryopreservation to success. For this purpose the rate of cooling for freezing process should be controlled properly, and the formation and growth of ice crystals should be suppressed by choosing effective cryoprotective agents (CPA).
Among the processes during cryopreservation that govern the survival of cells are ; (1)osmotic stress (excess expansion or shrinkage of cell), (2)intracellular freezing, (3)mechanical stress due to ice crystals formed outside the cell, and (4)biochemical toxicity. An ideal CPA must be capable of avoiding all of those stresses listed above.
One of the objectives of this research [Theme 1] is to select CPA that can avoid all the stresses (1)〜(4), and suppress the damage due to intracellular freezing by realizing vitrification (solidification without ice crystal formation) even under slow cooling rate. An active technique utilizing an electric field called
… More
electroporation seems promising.
Another objective of this research [Theme 2] is to establish the means for viability assessment of cells during and after the process of cryopreservation. We have developed the method of measuring mechanical properties of cells and tissues. Also we have carried out the quantitative analysis of ATP in the cells utilizing fluorescence effect. The summary of the research results is as follows.
Theme 1 : In order to select the CPA that may satisfy the criteria described above, we have carried out experiment with alginic acid and trehalose in addition to glycerol and DMSO employed conventionally. As the result of experiment, it has been found that alginic acid has a function of maintaining the form of cell membrane because of the high viscosity even under low concentration, and trehalose generates ice crystals outside the cell, thus being effective in suppressing intracellular freezing. In addition, introduction of CPA with high concentration into cells has been found to lead to satisfying result, though much more exprimental evidence is needed.
Theme 2 : In order to establish the means of assessing viability of biological tissue by measuring tenderness of small-scale specimen, we have developed a method of obtaining the mechanical properties of the tissue using ultrasonic pulses. At the same time, the ratio of survival of cells has been obtained by determining the quantity of ATP remaining in the cell making use of fluorescent light emitted from them. Less
|
