Tu R, Shen S H, Lin D, Hata C, Thyagarajan K, Noishiki Y, Quijano R C
TU Bioscience Labs, Tustin, California 92680.
J Biomed Mater Res. 1994 Jun;28(6):677-84. doi: 10.1002/jbm.820280604.
Collagen from a native tissue is fixed with a polyepoxy compound (PC) for use as a new biologic prosthetic material. Prior studies have shown that this biomaterial has comparable properties with collagen fixed with glutaraldehyde (GA), and thus has great promise for biomedical applications. A prior kinetic study indicated that the reaction between the functional groups of collagen and the multifunctional epoxy EX-313 is a 2.5th-order reaction. The purpose of this study was to understand the mechanism of the amino acid-PC reactions in a fixation process. Bovine arteries were fixed with a monofunctional PC (EX-131) and a multifunctional PC (EX-313) as a function of fixation time. A sequential fixation with a second fixative was used to identify the available remaining reactive sites from a prior fixation. The denaturation temperature (Td) was measured on each sample. Because the denaturation temperature is a direct indication of crosslinking of individual amino acids with the fixative, the increase in Td of a subsequent fixation may be indicative of the available remaining amino acids. The fixation index was measured on each sample to reflect the increase of fixation completion in a sequential fixation process. The fixation index and crosslink data also revealed that the reactive amino acids for EX-131 and EX-313 may not be exactly the same. The data in this study suggest that a monofunctional fixative can pre-react with the amino acids of collagen to effectively block further fixation of collagen with a second fixative. This amino acid masking may be associated with collagen branching. Collagen branching and its effect on denaturation temperature are described.
来自天然组织的胶原蛋白用聚环氧化合物（PC）固定，用作新型生物假体材料。先前的研究表明，这种生物材料具有与用戊二醛（GA）固定的胶原蛋白相当的性能，因此在生物医学应用方面具有巨大潜力。先前的动力学研究表明，胶原蛋白的官能团与多功能环氧树脂EX - 313之间的反应是2.5级反应。本研究的目的是了解固定过程中氨基酸与PC反应的机制。牛动脉用单官能PC（EX - 131）和多功能PC（EX - 313）进行固定，作为固定时间的函数。使用第二种固定剂进行顺序固定，以识别先前固定后可用的剩余反应位点。测量每个样品的变性温度（Td）。由于变性温度直接表明单个氨基酸与固定剂的交联，后续固定中Td的增加可能表明可用的剩余氨基酸。测量每个样品的固定指数，以反映顺序固定过程中固定完成程度的增加。固定指数和交联数据还表明，EX - 131和EX - 313的反应性氨基酸可能不完全相同。本研究中的数据表明，单官能固定剂可以与胶原蛋白的氨基酸预先反应，有效地阻止胶原蛋白与第二种固定剂的进一步固定。这种氨基酸掩蔽可能与胶原蛋白分支有关。描述了胶原蛋白分支及其对变性温度的影响。
