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 ----------

  Wowk B.  Leitl E.  Rasch CM.  Mesbah-Karimi N.  Harris SB.  Fahy GM.
  21st Century Medicine, Inc., Rancho Cucamonga, CA 91730, USA.
  Vitrification enhancement by synthetic ice blocking agents.
  Cryobiology.  40(3):228-36, 2000 May.
  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.

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