A first test of the hypothesis of biogenic magnetite-based heterogeneous ice-crystal nucleation in cryopreservation\
A first test of the hypothesis of biogenic magnetite-based heterogeneous ice-crystal nucleation in cryopreservation\
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DOI：
10.1016/j.cryobiol.2016.04.003
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发表时间：
2016-06-01
期刊：
影响因子：
2.7
通讯作者：
Kirschvink, Joseph L.
中科院分区：
文献类型：
--
作者：
Kobayashi, Atsuko;Golash, Harry N.;Kirschvink, Joseph L.
一个突出的生物物理学难题是集中在弱，极低频振荡磁场的明显能力，以提高许多生物组织的冷冻保存。最近的一种理论认为，这些弱磁场可能会抑制生物磁铁矿（Fe 3 O 4，一种反立方尖晶石）纳米晶体上的冰晶成核，这些生物磁铁矿存在于许多植物和动物组织中，使它们振荡。在这个理论中，磁致机械振荡破坏了水分子在磁铁矿纳米晶体表面成核的能力。然而，磁铁矿晶格作为非均质冰晶成核模板的能力尚不清楚，特别是对于10-100 nm尺寸范围内的颗粒。在这里，我们报告说，加入微量的细分散的磁铁矿到超纯水样品大大降低了过冷的发病率，如在实验中测量使用的控制冷冻装置与多个热电偶。SQUID磁力测定法用于量化水样中的磁铁矿的纳克水平。我们还报告了冰的体积变化和过冷度之间的关系，这可能表明过冷水结晶过程中的脱气作用较低。除了支持生物磁铁矿在许多组织中的冰晶成核作用之外，磁铁矿纳米晶体还可以提供各种工业过程中所需的廉价、无毒和非致病性的冰成核剂，以及影响许多自然环境中冰晶成核的动力学。(C)2016作者爱思唯尔公司出版这是CC BY-NC-ND许可下的开放获取文章。
An outstanding biophysical puzzle is focused on the apparent ability of weak, extremely low-frequency oscillating magnetic fields to enhance cryopreservation of many biological tissues. A recent theory holds that these weak magnetic fields could be inhibiting ice-crystal nucleation on the nanocrystals of biological magnetite (Fe3O4, an inverse cubic spinel) that are present in many plant and animal tissues by causing them to oscillate. In this theory, magnetically-induced mechanical oscillations disrupt the ability of water molecules to nucleate on the surface of the magnetite nanocrystals. However, the ability of the magnetite crystal lattice to serve as a template for heterogeneous ice crystal nucleation is as yet unknown, particularly for particles in the 10-100 nm size range. Here we report that the addition of trace amounts of finely-dispersed magnetite into ultrapure water samples reduces strongly the incidence of supercooling, as measured in experiments conducted using a controlled freezing apparatus with multiple thermocouples. SQUID magnetometry was used to quantify nanogram levels of magnetite in the water samples. We also report a relationship between the volume change of ice, and the degree of supercooling, that may indicate lower degassing during the crystallization of supercooled water. In addition to supporting the role of ice-crystal nucleation by biogenic magnetite in many tissues, magnetite nano crystals could provide inexpensive, non-toxic, and non-pathogenic ice nucleating agents needed in a variety of industrial processes, as well as influencing the dynamics of ice crystal nucleation in many natural environments. (C) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license.