Lundberg P, Kuchel P W
Department of Physical Chemistry, University of Umeå, Sweden.
Magn Reson Med. 1997 Jan;37(1):44-52. doi: 10.1002/mrm.1910370108.
Cells immobilized in gels experience potential metabolic restrictions in the form of reduced diffusion rates of metabolites and ions and their possible selective adsorption on the gel matrix. Diffusion and relaxation characteristics of common solutes in agarose and barium alginate gels were investigated at 37 degrees C by using 1H PFGSE and 23Na TQF NMR spectroscopy. Glucose, glycine, alanine, lactate, sodium ions, and HDO were studied. There were no selective interactions between any of the metabolites and the gel materials but the diffusion coefficients were uniformly reduced. The effects of metabolite diffusion and utilization, in gel beads and threads containing cells, were simulated by using a reaction diffusion model incorporating the measured diffusion coefficients. Metabolism is expected to be very significantly limited by diffusion of solutes to and from the cells that are centrally located within gel threads or spheres of radius approximately 2.0 mm, which is a commonly used size.
固定在凝胶中的细胞会因代谢物和离子扩散速率降低以及它们可能在凝胶基质上的选择性吸附而面临潜在的代谢限制。通过使用1H PFGSE和23Na TQF NMR光谱，在37摄氏度下研究了琼脂糖和海藻酸钡凝胶中常见溶质的扩散和弛豫特性。研究了葡萄糖、甘氨酸、丙氨酸、乳酸、钠离子和重水。代谢物与凝胶材料之间没有选择性相互作用，但扩散系数均一降低。通过使用包含测量扩散系数的反应扩散模型，模拟了凝胶珠和含有细胞的细丝中代谢物扩散和利用的影响。对于位于半径约2.0毫米的凝胶细丝或球体中心的细胞，溶质进出细胞的扩散预计会非常显著地限制代谢，这是常用的尺寸。
