Department Food Science, University of Guelph, Guelph, ON, N1G2W1, Canada.
NMR Centre, University of Guelph, Guelph, ON, N1G2W1, Canada.
Sci Rep. 2018 Jun 27;8(1):9744. doi: 10.1038/s41598-018-28123-4.
We recently reported that the water holding capacity of myofibrillar protein hydrogels could be increased upon addition of small amounts of microparticles, particularly glass microspheres. Glass microspheres were found to decrease the spin-spin relaxation time (T) of water protons in the gels, which was interpreted as enhanced water binding by the glass. We were thus interested in determining whether the observed effects on water proton relaxation were a direct consequence of water-glass interactions. Here we show how glass microspheres reduce the mobility of pure water, reflected in large decreases in the T of water protons, decreases in the self-diffusion coefficient of water molecules, a lower water activity, and strengthening of O-H bonds. Even though glass is considered an inert material, glass microspheres were shown to inhibit the growth of human embryonic kidney cells, and stimulate or inhibit the growth of leukemia and monocytic lymphoma cells in vitro, depending on dose and time. The germination of alfalfa seeds and the growth of E.coli cells were also inhibited upon exposure to glass microspheres. This work indicates that the properties and behavior of materials, even ones considered inert, can be affected by their size. These observations suggest possible toxicological consequences of exposure to microparticles, but also open us possibilities to affect cellular/organism function via modulation of macromolecular hydration.
我们最近报道称，在添加少量微粒（特别是玻璃微球）的情况下，肌原纤维蛋白水凝胶的持水能力会增加。研究发现，玻璃微球降低了凝胶中水质子的自旋-自旋弛豫时间（T），这被解释为玻璃增强了水的结合能力。因此，我们有兴趣确定对水质子弛豫的观察到的影响是否是水-玻璃相互作用的直接结果。在这里，我们展示了玻璃微球如何降低纯水的流动性，这反映在水质子 T 的大幅降低、水分子自扩散系数的降低、水活度的降低以及 O-H 键的增强。尽管玻璃被认为是一种惰性材料，但玻璃微球被证明可以抑制人胚肾细胞的生长，并在体外刺激或抑制白血病和单核细胞淋巴瘤细胞的生长，具体取决于剂量和时间。暴露于玻璃微球也会抑制紫花苜蓿种子的发芽和大肠杆菌细胞的生长。这项工作表明，即使是被认为是惰性的材料，其性质和行为也可能受到其尺寸的影响。这些观察结果表明，暴露于微粒可能会产生毒理学后果，但也为我们通过调节生物大分子水合作用来影响细胞/生物体功能提供了可能性。
