Microcalorimetric studies on the adsorption of DNA by soil colloidal particles
Microcalorimetric studies on the adsorption of DNA by soil colloidal particles
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DOI：
10.1016/j.colsurfb.2006.02.011
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发表时间：
2006-04-15
影响因子：
5.8
通讯作者：
Liang, Wei
中科院分区：
文献类型：
--
作者：
Cai, Peng;Huang, Qiaoyun;Liang, Wei
采用TAM空气等温量热仪测定了DNA在8种恒电荷和可变电荷土壤胶体组分上的吸附速率。利用平衡吸附法研究了DNA在土壤胶体上的吸附。用Langmuirean模型拟合的吸附等温线表明，可变电荷土壤胶体对DNA的亲和力高于固定电荷土壤胶体。更紧密结合的DNA分子上观察到粗粘土和无机粘土比细粘土和有机粘土，分别。固定电荷土壤胶体对DNA的吸附能力高于可变电荷土壤胶体。DNA在有机粘土上的吸附是吸热的，而在无机粘土上的吸附是放热的。脱水作用和静电排斥作用是导致DNA在有机粘土上吸附能力提高的主要原因，而氢键作用、配体交换作用和静电吸引作用则是导致DNA在无机粘土上吸附能力降低的主要原因。本研究中提出的热力学参数提供了重要的意义，进一步深入了解DNA吸附在土壤颗粒的机制。(c)2006 Elsevier B.V.保留所有权利。
This study applied TAM air isothermal calorimeter to measure the adsorption enthalpies of DNA on eight colloidal fractions from permanent-charge and variable-charge soils. The adsorption of DNA on soil colloids was also examined by equilibrium adsorption analysis. The data evaluated from isotherms fitted by Langmuirean model revealed that the affinity of DNA for variable-charge soil colloids was higher than that for permanent-charge soil colloids. More tightly bound DNA molecules were observed on coarse clays and inorganic clays than on fine clays and organic clays, respectively. The adsorption enthalpies of DNA on permanent-charge soil colloids were higher than those on variable-charge soil colloids. DNA adsorption on organic clays is endothermic, whereas that on inorganic clays is exothermic. Dehydration and electrostatic repulsion were considered to cause the higher adsorption enthalpies of DNA with organic clays, while hydrogen bonding, ligand exchange and electrostatic attraction result in the lower DNA adsorption enthalpies on inorganic clays. The thermodynamic parameters presented in this study have important implication for providing further insight into mechanisms of the adsorption of DNA on soil particles. (c) 2006 Elsevier B.V. All rights reserved.