Gao Chaohong, Bai Jing, He Yanting, Zheng Qiong, Ma Wende, Lei Zhixian, Zhang Mingyue, Wu Jie, Fu Fengfu, Lin Zian
Ministry of Education Key Laboratory of Analytical Science for Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, College of Chemistry , Fuzhou University , Fuzhou , Fujian 350116 , China.
ACS Appl Mater Interfaces. 2019 Apr 10;11(14):13735-13741. doi: 10.1021/acsami.9b03330. Epub 2019 Mar 27.
Chemical modification of covalent organic frameworks (COFs) is indispensable for integrating functionalities of greater complexity and accessing advanced COF materials suitable for more potential applications. Reported here is a novel strategy for fabricating controllable core-shell structured Zr-immobilized magnetic COFs (MCNC@COF@Zr) composed of a high-magnetic-response magnetic colloid nanocrystal cluster (MCNC) core, Zr ion-functionalized two-dimensional COFs as the shell by sequential postsynthetic functionalization and, for the first time, the application of the MCNC@COF@Zr composites for efficient and selective enrichment of phosphopeptides. The as-prepared MCNC@COF@Zr composites possess regular porosity with large surface areas, high Zr loading amount, strong magnetic responsiveness, and good thermal/chemical stability, which can serve as an ideal adsorbent for selective enrichment of phosphopeptides and simultaneous size exclusion of biomacromolecules, such as proteins. The high detection sensitivity (10 fmol) together with the excellent recovery of phosphopeptides is also obtained. These outstanding features suggest that the MCNC@COF@Zr composites are of great benefit for pretreatment prior to mass spectrometry analysis of phosphopeptides. In addition, the performance of the developed approach in selective enrichment of phosphopeptides from the tryptic digests of defatted milk and directly specific capture of endogenous phosphopeptides from human serum gives powerful proof for its high selectivity and effectiveness in identifying the low-abundance phosphopeptides from complicated biological samples. This study not only provides a strategy for versatile functionalization of magnetic COFs but also opens a new avenue in their use in phosphoproteome analysis.
共价有机框架（COF）的化学修饰对于整合更复杂的功能以及获得适用于更多潜在应用的先进COF材料而言不可或缺。本文报道了一种制备可控核壳结构的固定锆磁性COF（MCNC@COF@Zr）的新策略，该结构由高磁响应磁性胶体纳米晶体簇（MCNC）核、通过顺序后合成功能化形成的作为壳层的锆离子功能化二维COF组成，并且首次将MCNC@COF@Zr复合材料用于高效、选择性富集磷酸肽。所制备的MCNC@COF@Zr复合材料具有规则的孔隙率、大表面积、高锆负载量、强磁响应性以及良好的热/化学稳定性，可作为选择性富集磷酸肽并同时对蛋白质等生物大分子进行尺寸排阻的理想吸附剂。还获得了高检测灵敏度（10 fmol）以及优异的磷酸肽回收率。这些突出特性表明，MCNC@COF@Zr复合材料对于磷酸肽质谱分析前的预处理极为有益。此外，所开发方法在从脱脂牛奶胰蛋白酶消化物中选择性富集磷酸肽以及直接特异性捕获人血清中内源性磷酸肽方面的性能，有力地证明了其在从复杂生物样品中鉴定低丰度磷酸肽方面的高选择性和有效性。本研究不仅为磁性COF的多功能化提供了一种策略，还为其在磷酸化蛋白质组分析中的应用开辟了一条新途径。
