MALDI-TOF imaging mass spectrometry (IMS) is a common technique used for analyzing tissue samples, as it allows the user to detect multiple different analytes simultaneously. However, the detection and analysis of these analytes may sometimes be hampered due to the presence of contaminants in the tissue microenvironment, which leads to ion suppression. This challenge necessitates the development of an active extraction technique to selectively isolate analytes of interest without compromising their spatial localization within a tissue sample. This study proposes a magnetic bead-based active extraction approach to selectively sequester peptides of interest from tissue samples. The technique utilizes a heterobifunctional cross-linker to covalently bind peptides with free primary amine groups to functionalized magnetic beads. The cross-linked peptides can then be collected using a transfer magnet and imaged using MALDI-TOF IMS. We have established that this technique not only successfully isolates peptides both in-solution and on a solid surface, but also extracts peptides from a tissue section without significantly compromising their spatial localization. This novel method provides the means to detect a unique subset of peptides from tissue sections when compared to unextracted tryptically digested tissue, all while minimizing the presence of contaminants and maintaining spatial localization.

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基于磁珠的肽提取方法用于组织成像

MALDI-TOF成像质谱（IMS）是用于分析组织样本的常用技术，因为它允许用户同时检测多种不同的分析物。但是，由于组织微环境中污染物的存在，有时可能会阻碍这些分析物的检测和分析，从而导致离子抑制。这一挑战需要开发一种主动提取技术，以选择性地分离目标分析物而不损害其在组织样品中的空间定位。这项研究提出了一种基于磁珠的主动提取方法，以从组织样品中选择性隔离目标肽。该技术利用异双功能交联剂将带有游离伯胺基团的肽与功能化的磁珠共价结合。然后可以使用转移磁体收集交联的肽，并使用MALDI-TOF IMS进行成像。我们已经确定，该技术不仅可以成功地分离溶液中和固体表面上的肽，而且还可以从组织切片中提取肽，而不会显着损害其空间定位。与未提取的经胰蛋白酶消化的组织相比，这种新颖的方法提供了从组织切片中检测肽的独特子集的方法，同时还使污染物的存在最小化并保持空间定位。而且还可以从组织切片中提取肽，而不会显着损害其空间定位。与未提取的经胰蛋白酶消化的组织相比，这种新颖的方法提供了从组织切片中检测肽的独特子集的方法，同时还使污染物的存在最小化并保持空间定位。而且还可以从组织切片中提取肽，而不会显着损害其空间定位。与未提取的经胰蛋白酶消化的组织相比，这种新颖的方法提供了从组织切片中检测肽的独特子集的方法，同时还使污染物的存在最小化并保持空间定位。