Affiliations: [a] Department of Chemical Engineering and Chemical Technology, Imperial College of Science, Technology and Medicine, London, UK | [b] Department of Physiology and Biophysics, Imperial College School of Medicine at St Mary’s, London, UK
Note: [*] Reprint requests to: M. W. Rampling, Department of Physiology and Biophysics, Imperial College School of Medicine at St. Mary’s, Norfolk Place, London W2 lPG, UK; Fax: ++44(0) 171 723 7185; E-mail: m.rampling@ic.ac.uk
Abstract: Freezing whole blood in bulk usually results in severe cellular destruction through the action of ice crystals and osmotic effects in the freezing liquid. The potential of flash freezing blood aerosols onto a liquid nitrogen surface as a means of inhibiting cellular damage was studied in this work. Three commercial spraying devices were employed to spray-freeze either whole blood or concentrated erythrocyte suspensions, using hydroxyethyl starch (HES) as a cryoprotectant. The integrity and viability of the processed cells were assessed by measuring gross rheological properties and the extent of hemolysis. Cells were found to be susceptible to the very high shear stresses imposed by some of the spraying devices. Bulk freezing of blood, even in the presence of the cryoprotectant, resulted in complete cellular destruction. Whereas flash freezing was capable of substantially reducing the level of hemolysis to 12.6% and preserving the cellular deform ability.
