CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
J Chromatogr A. 2013 Feb 1;1275:9-16. doi: 10.1016/j.chroma.2012.12.023. Epub 2012 Dec 19.
Some compounds of low abundance in biological samples play important roles in bioprocesses. However, the detection of these compounds at inherently trace concentrations with interference from a complex matrix is difficult. New materials for sample pretreatment are essential for the removal of interferences and for selective enrichment. In this study, echinus-like Fe(3)O(4)@TiO(2) core-shell-structured microspheres (echinus-like microspheres) have been synthesized for the first time. Rutile phase TiO(2) nanorods with a length of approximately 300 nm and width of approximately 60 nm are arranged regularly on the surface of the microspheres. This novel type of material exhibited good selectivity and adsorption capacity toward phosphate-containing compounds. In proteomics research, the echinus-like microspheres were used to selectively enrich phosphopeptides from complex peptide mixtures. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) analysis showed that fourteen phosphopeptides were detected from α-casein tryptic digests after enrichment. Even in peptide mixtures that contained highly abundant nonphosphorylated peptides with interference from bovine serum albumin, these phospopeptides could still be selectively trapped with little nonspecific adsorption. In metabolomics studies, the echinus-like microspheres were further used to selectively remove phosphocholines (PCs) and lysophosphocholines (LPCs), which are the main matrix interferences for the detection of metabolites of low abundance in plasma. Liquid chromatography-quadrupole time-of-flight mass spectrometry was used to perform the metabolic profiling of plasma. The high concentrations of PCs and LPCs were effectively eliminated, and many endogenous metabolites of low abundance were enhanced or even observed for the first time. All of the results suggest that echinus-like microspheres have potential applications in proteomics and metabolomics to improve the detection sensitivity of important compounds.
一些在生物样本中含量较低的化合物在生物过程中起着重要作用。然而，由于复杂基质的干扰，这些化合物在痕量浓度下的检测非常困难。因此，需要新型样品预处理材料来去除干扰并进行选择性富集。本研究首次合成了具有海胆状结构的 Fe(3)O(4)@TiO(2)核壳结构微球（海胆状微球）。微球表面规则排列着长度约为 300nm、宽度约为 60nm 的锐钛矿相 TiO(2)纳米棒。这种新型材料对含磷化合物表现出良好的选择性和吸附能力。在蛋白质组学研究中，海胆状微球用于从复杂肽混合物中选择性富集磷酸肽。基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF/MS）分析表明，从α-酪蛋白胰酶消化物中经富集后检测到 14 种磷酸肽。即使在含有高丰度非磷酸化肽且受牛血清白蛋白干扰的肽混合物中，这些磷酸肽也可以被选择性捕获，且几乎没有非特异性吸附。在代谢组学研究中，海胆状微球进一步用于选择性去除磷酸胆碱（PC）和溶血磷酸胆碱（LPC），它们是检测低丰度血浆代谢物时的主要基质干扰物。采用液相色谱-四极杆飞行时间质谱法进行代谢物谱分析。高浓度的 PC 和 LPC 被有效去除，许多低丰度的内源性代谢物得到增强，甚至首次被观察到。所有结果表明，海胆状微球在蛋白质组学和代谢组学中具有潜在的应用前景，可提高重要化合物的检测灵敏度。
