Liu Jia-Wei, Yang Ting, Chen Shuai, Chen Xu-Wei, Wang Jian-Hua
Research Center for Analytical Sciences, College of Sciences, Northeastern University, Box 332, Shenyang 110819, China.
J Mater Chem B. 2013 Feb 14;1(6):810-818. doi: 10.1039/c2tb00334a. Epub 2012 Dec 6.
A novel functionalized graphene-based composite is prepared by successive modification of graphene oxide (GO) with epichlorohydrin (ECH), iminodiacetic acid (IDA) and 1-phenylboronic acid (1-PBA) through covalent functionalization and then chelating with nickel ions. Characterizations by FT-IR, XRD, SEM, TGA and ICP-MS demonstrate the successful modification of the graphene surface, resulting in a GO-PBA-IDA-Ni composite with a Ni immobilization amount of 3.01 × 10 mol g. The composite shows favorable selectivity for the adsorption of lysozyme (Lys). In practice, a homogeneous GO-PBA-IDA-Ni film with a thickness of ca. 1.0 μm is fabricated by filtering the composite through a cellulose membrane with a pore aperture of 1.2 μm. The GO-PBA-IDA-Ni film is subsequently fastened into a rounded membrane cartridge and incorporated into a sequential injection system for on-line selective isolation of Lys. An adsorption efficiency of ca. 96% is achieved for 25 μg ml Lys in 500 μl of sample solution at a loading rate of 5 μl s. Metal affinity and electrostatic interactions are the main driving forces for governing the protein adsorption behaviors. The retained Lys is readily recovered by a borate buffer (pH 10) containing 1.0 mol l NaCl and 20 mmol l imidazole, giving rise to a recovery of ca. 90%. The practical applicability of the composites is demonstrated by selective isolation of Lys from chicken egg white, and SDS-PAGE assay indicates that Lys is selectively isolated with high purity from complex matrices.
通过用环氧氯丙烷（ECH）、亚氨基二乙酸（IDA）和1-苯硼酸（1-PBA）对氧化石墨烯（GO）进行连续共价功能化修饰，然后与镍离子螯合，制备了一种新型功能化石墨烯基复合材料。傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、热重分析（TGA）和电感耦合等离子体质谱（ICP-MS）表征表明石墨烯表面成功改性，得到了镍固定量为3.01×10 mol g的GO-PBA-IDA-Ni复合材料。该复合材料对溶菌酶（Lys）的吸附表现出良好的选择性。实际上，通过将复合材料过滤通过孔径为1.2μm的纤维素膜，制备了厚度约为1.0μm的均匀GO-PBA-IDA-Ni膜。随后将GO-PBA-IDA-Ni膜固定到圆形膜盒中，并集成到顺序注射系统中用于Lys的在线选择性分离。在5μl s的进样速率下，对500μl样品溶液中25μg ml的Lys实现了约96%的吸附效率。金属亲和力和静电相互作用是控制蛋白质吸附行为的主要驱动力。保留的Lys很容易通过含有1.0 mol l NaCl和20 mmol l咪唑的硼酸盐缓冲液（pH 10）回收，回收率约为90%。通过从鸡蛋白中选择性分离Lys证明了该复合材料的实际适用性，十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表明Lys从复杂基质中被选择性地高纯度分离出来。
