Efficient enrichment and identification of phosphopeptides are of great significance in biological applications. Glycocyamine functionalized magnetic layered double hydroxides (Fe3O4@LDH@NH2-GAA) was fabricated through an easy process. The magnetic composite possessed high surface area, good biocompatibility, and fast magnetic response. Fe3O4@LDH@NH2-GAA, combining not only metal ions (Cu2+ and Ga3+) in LDH but also functional guanidyl groups in glycocyamine, offered multiple affinity sites for phosphopeptides enrichment. With these favorable characters, it exhibited high selectivity (β-casein: bovine serum albumin = 1:5000), low detection limit (0.1 fmol), satisfactory enrichment recovery (94.5%), high adsorption capacity (82.4 mg g-1), and good repetitiveness. Moreover, the efficient enrichment of phosphopeptides by Fe3O4@LDH@NH2-GAA from nonfat milk, human saliva, serum, and A549 cell lysates further confirmed its great potential for trace biological detection and proteomic analysis.

中文翻译：

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用于富集痕量磷酸肽的具有多个亲和位点的糖胺功能化磁性层状双氢氧化物

磷酸肽的有效富集和鉴定在生物学应用中具有重要意义。糖胺功能化磁性层状双氢氧化物（Fe3O4@LDH@NH2-GAA）是通过简单的工艺制备的。该磁性复合材料具有高表面积、良好的生物相容性和快速的磁响应。Fe3O4@LDH@NH2-GAA不仅结合了LDH中的金属离子（Cu2+和Ga3+），而且结合了糖胺中的功能性胍基，为磷酸肽的富集提供了多个亲和位点。凭借这些有利的特性，它表现出高选择性（β-酪蛋白：牛血清白蛋白 = 1:5000）、低检测限（0.1 fmol）、令人满意的富集回收率（94.5%）、高吸附容量（82.4 mg g-1）、和良好的重复性。而且，