X-Message-Number: 14559 Date: Wed, 27 Sep 2000 10:14:44 -0700 (PDT) From: Doug Skrecky <> Subject: polyvinyl alcohol ice blocker I wonder what 10% polyvinyl alcohol would do? ---------- Forwarded message ---------- Authors Wowk B. Leitl E. Rasch CM. Mesbah-Karimi N. Harris SB. Fahy GM. Institution 21st Century Medicine, Inc., Rancho Cucamonga, CA 91730, USA. Title Vitrification enhancement by synthetic ice blocking agents. Source Cryobiology. 40(3):228-36, 2000 May. Abstract Small concentrations of the synthetic polymer polyvinyl alcohol (PVA) were found to inhibit formation of ice in water/cryoprotectant solutions. Ice inhibition improved with decreasing molecular weight. A PVA copolymer of molecular weight 2 kDa consisting of 20% vinyl acetate was found to be particularly effective. PVA copolymer concentrations of 0.001, 0.01, 0.1, and 1% w/w decreased the concentration of glycerol required to vitrify in a 10-ml volume by 1, 3, 4, and 5% w/w, respectively. Dimethyl sulfoxide concentrations required for vitrification were also reduced by 1, 2, 2, and 3% w/w, respectively. Crystallization of ice on borosilicate glass in contact with cryoprotectant solutions was inhibited by only 1 ppm of PVA copolymer. Devitrification of ethylene glycol solutions was also strongly inhibited by PVA copolymer. Visual observation and differential scanning calorimeter data suggest that PVA blocks ice primarily by inhibition of heterogeneous nucleation. PVA thus appears to preferentially bind and inactivate heterogeneous nucleators and/or nascent ice crystals in a manner similar to that of natural antifreeze proteins found in cold-hardy fish and insects. Synthetic PVA-derived ice blocking agents can be produced much less expensively than antifreeze proteins, offering new opportunities for improving cryopreservation by vitrification. Copyright 2000 Academic Press. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=14559