Electromagnetic re-warming of cryopreserved tissues: effect of choice of cryoprotectant and sample shape on uniformity of heating.
A method that has been proposed for the cryopreservation of tissues and organs is to add a cryoprotective agent (CPA) in sufficient concentration to allow vitrification, and to use rapid electromagnetic heating to prevent the formation of ice crystals during the re-warming. We have compared the physical and biological properties of four CPAs, measuring the speed and uniformity of heating in a 36 mm sphere placed in a 434 MHz applicator, and the toxicity to ECV304 endothelial cells. Ethanediol and dimethyl sulfoxide were found to be suitable for rapid, uniform heating but toxic to the endothelial cells at vitrifying concentrations. Butane-2,3-diol was less toxic, but the heating patterns were unacceptably non-uniform. Propane-1,2-diol was not significantly more toxic than butane-2,3-diol, and did allow uniform heating. It is therefore the best choice of CPA for the vitrification of tissues. We have shown that the uniformity of heating correlates with the dielectric properties of the perfusate. Furthermore, we have shown that uniform heating is feasible in non-spherical samples provided they are approximately ellipsoidal.
Robinson
Martin P
MP
Department of Electronics, University of York, Heslington, UK. mpr@ohm.york.ac.uk
Wusteman
Monica C
MC
Wang
Lihong
L
Pegg
David E
DE
D002072:Butylene Glycols / Q000528:radiation effects / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000528:radiation effects* / Q000633:toxicity*; D004121:Dimethyl Sulfoxide / Q000528:radiation effects / Q000633:toxicity; D004574:Electromagnetic Fields; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000528:radiation effects*; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008623:Mercaptoethanol / Q000031:analogs & derivatives* / Q000528:radiation effects / Q000633:toxicity; D019946:Propylene Glycol / Q000528:radiation effects / Q000633:toxicity; D000078702:Radiofrequency Therapy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014471:Umbilical Veins
D002072:Butylene Glycols; D003451:Cryoprotective Agents; C026978:2,3-butylene glycol; D008623:Mercaptoethanol; D019946:Propylene Glycol; C031854:1,2-ethanedithiol; D004121:Dimethyl Sulfoxide