Adsorption kinetics of carcinogens to DNA liquid crystalline gel beads
Adsorption kinetics of carcinogens to DNA liquid crystalline gel beads
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DOI：
10.1021/la701379q
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发表时间：
2007-09-25
期刊：
影响因子：
3.9
通讯作者：
Yamamoto, Takao
中科院分区：
文献类型：
--
作者：
Furusawa, Kazuya;Wakamatsu, Masako;Yamamoto, Takao
从理论和实验两方面研究了DNA液晶凝胶（LCG）微球在水分散体系中对吖啶橙子（AO）和联苯（BP）的吸附行为。基于非平衡热力学的理论考虑，预测吸附过程的时间过程用标度方程表示，标度的吸附致癌物分子数h用标度的浸泡时间（t）的平方根表示，（n）的平方根与早期阶段的根成正比，而对于（n（0））/波浪线> 1，它用幂律函数1 -（n）/波浪线与（（t（e））/波浪线-（t）/波浪线）（3/2）成比例表示，并且用指数方程（n（0））/波浪线-（n）/波浪线与e成比例表示（-t/alpha tau 0），对于（n（0）），在吸附的后期阶段大于1。这里，（n（0））是分散溶液中致癌物分子的初始数目与珠粒中致癌物分子吸附位点数目的比率，（t（e））是吸附的比例平衡时间，tau（0）是吸附的时间常数，α是常数。模拟结果与实验结果吻合较好，拟合参数（n（0））和τ（0）均随制备微球所用氯化钴浓度的增加而增大，当氯化钴浓度大于400 mM时，拟合参数均达到饱和，而BP的吸附过程可用平方根函数表示。这些结果表明：（1）吸附初期的吸附过程是由致癌物分子与DNA珠的扩散限制性结合来解释的，吸附初期的时间范围取决于溶解度（AO在水中的溶解度高，而BP在水中的溶解度低）;（2）吸附后期的吸附过程取决于吸附位点和致癌物分子数量的平衡。
Adsorption behaviors of acridine orange(AO) and biphenyl (BP) to DNA liquid crystalline gel (LCG) beads in aqueous dispersing solution have been studied theoretically and experimentally. A theoretical consideration based on nonequilibrium thermodynamics predicted that the time course of the adsorption process is expressed with a scaled equation, and a scaled number of adsorbed carcinogen molecules h is expressed with the square root of a scaled immersion time (t) over tilde, (n) over tilde proportional to root(t) over tilde at early stage, whereas it is expressed with a power law function 1 -(n) over tilde proportional to ((t(e)) over tilde - (t) over tilde)(3/2) for (n(0)) over tilde > 1 and an exponential equation (n(0)) over tilde - (n) over tilde proportional to e(-t/alpha tau 0) for (n(0)) over tilde > 1 at later stages of adsorption. Here, (n(0)) over tilde is the ratio of the initial number of carcinogen molecules in the dispersing solution to the number of the sites of adsorption of carcinogen molecules in the beads, (t(e)) over tilde is the scaled equilibrium time of adsorption, tau(0) is a time constant for adsorption, and alpha is a constant. Observed adsorption processes for AO were well expressed by the predicted ones, and the fitting parameters (n(0)) over tilde and tau(0) increased with increasing cobalt chloride concentration C-Co used for preparation of the beads, and both saturated above C-Co >= 400 mM for the adsorption of AO, whereas the adsorption processes for BP were expressed with the square root function. These results indicate that (1) the adsorption process at early stage is explained by diffusion-limited binding of the carcinogen molecules to DNA beads, and the time range of the early stage depends on the solubility (the solubility of AO in water is high whereas that of BP is low); and (2) the process at later stages depends on the balance of the numbers of adsorption sites and carcinogen molecules.