Abstract
The advantages of microencapsulated cells over those of suspended cells were evaluated for improving viability in cryopreservation. Rat pheochromocytoma (PC12) cells were selected as the test biological cells and then microencapsulated in alginatepolylysine-alginate membranes. These microencapsulated PC12 cells were frozen by differential scanning calorimetry (DSC) at various cooling rates, from 0.5 to 10°C/min. Their latent heat was measured during freezing from 4 to -80°C. The post-thaw viability was evaluated by dopamine-concentration measurement and by trypan blue exclusion assay. Results showed that at cooling rates of 0.5 and 1°C/min, the latent heat of microencapsulated PC12 cells was lower than that of suspended cells. This lower latent heat is caused by the fact that the extra-microcapsule froze and the intracapsule remained unfrozen due to the formation of ice crystals in the extra-capsule space. The post-thaw viability of microencapsulated PC12 cells was improved when the cooling rate was 0.5 or 1°C/min, compared with that of suspended cells. Therefore, in microencapsulated PC12 cells, maintaining the intra-microcapsules in an unfrozen state during freezing reduces the solution effect and thus improves the post-thaw viability.
Original language | English |
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Pages (from-to) | 937-945 |
Number of pages | 9 |
Journal | JSME International Journal, Series C: Mechanical Systems, Machine Elements and Manufacturing |
Volume | 44 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2001 Dec |
Externally published | Yes |
Keywords
- Alginate-polylysine-alginate membranes
- Cryopreservation
- Differential scanning calorimetry
- Dopamine-concentration measurement
- Freezing
- Heat transfer
- Microencapsulation
- PC12 cells
ASJC Scopus subject areas
- Industrial and Manufacturing Engineering
- Mechanical Engineering