Concentration Dependent Effects of Bovine Serum Albumin on Graphene Oxide Colloidal Stability in Aquatic Environment
Concentration Dependent Effects of Bovine Serum Albumin on Graphene Oxide Colloidal Stability in Aquatic Environment
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牛血清白蛋白对水生环境中氧化石墨烯胶体稳定性的浓度依赖性影响
DOI：
10.1021/acs.est.7b06218
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发表时间：
2018
影响因子：
11.4
通讯作者：
Lingyan Zhu
中科院分区：
文献类型：
--
作者：
Binbin Sun;Yinqing Zhang;Wei Chen;Kunkun Wang;Lingyan Zhu
采用时间分辨动态光散射技术研究了pH 5.5时，模型球状蛋白（牛血清白蛋白，BSA）对水环境中氧化石墨烯（GO）聚集动力学的影响.无BSA的GO作为电解质浓度（NaCl、MgCl 2和CaCl 2）的函数的聚集动力学遵循传统的Derjaguin-Landau-Verwey-Overbeek（DLVO）理论，并且临界凝固浓度（CCC）分别为190、5.41和1.61 mM。由于存在BSA，其以浓度依赖性方式影响GO稳定性。在低于CCC值的固定电解质浓度下，例如120 mM NaCl，当BSA浓度从0增加到66.5 mg C/L时，GO的附着效率从0.08增加到1，然后逐渐降低，最后达到零。低浓度BSA降低GO的稳定性主要是由于BSA的正电荷赖氨酸基团与GO的负电荷基团之间的静电结合以及双电层压缩效应。随着BSA浓度的增加，越来越多的BSA分子被吸附在GO上，产生强烈的空间排斥作用，最终占据优势并稳定GO。这些结果提供了关于在环境相关条件下天然有机物质对GO稳定性的浓度依赖性影响的重要信息。
The impacts of a model globular protein (bovine serum albumin, BSA) on aggregation kinetics of graphene oxide (GO) in aquatic environment were investigated through time-resolved dynamic light scattering at pH 5.5. Aggregation kinetics of GO without BSA as a function of electrolyte concentrations (NaCl, MgCl2, and CaCl2) followed the traditional Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, and the critical coagulation concentration (CCC) was 190, 5.41, and 1.61 mM, respectively. As BSA was present, it affected the GO stability in a concentration dependent manner. At fixed electrolyte concentrations below the CCC values, for example 120 mM NaCl, the attachment efficiency of GO increased from 0.08 to 1, then decreased gradually and finally reached up to zero as BSA concentration increased from 0 to 66.5 mg C/L. The low-concentration BSA depressed GO stability mainly due to electrostatic binding between the positively charged lysine groups of BSA and negatively charged groups of GO, as well as double layer compression effect. With the increase of BSA concentration, more and more BSA molecules were adsorbed on GO, leading to strong steric repulsion which finally predominated and stabilized the GO. These results provided significant information about the concentration dependent effects of natural organic matters on GO stability under environmentally relevant conditions.