The use of lactosylated Fe₃O₄ magnetic nanoparticles (MNP@LAC) has been explored as affinity probes against ricin B based on galactose-ricin B binding interactions. Lactose was bound onto the surface of aminated MNPs through the Maillard reaction. The enrichment of ricin B took ~1 h by incubating MNP@LAC with samples under shaking at room temperature, followed by magnetic isolation. The resultant MNP@LAC-ricin B conjugates were characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The limit of detection toward ricin B was ~3 nM by using the developed method. It was possible to detect the peptides derived from the tryptic digest of trace ricin B (~0.39 nM) enriched by the MNP@LAC probes followed by tryptic digestion and MALDI-MS analysis. The feasibility of using the developed method for detection of ricin B from complex white corn starch samples spiked with trace ricin B was demonstrated.

Graphical abstract

中文翻译：

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基于功能性磁性纳米颗粒的亲和探针用于 MALDI 质谱检测蓖麻毒蛋白 B

乳糖基化Fe ₃ O ₄的用途基于半乳糖-蓖麻蛋白 B 结合相互作用，磁性纳米颗粒 (MNP@LAC) 已被探索作为针对蓖麻蛋白 B 的亲和探针。乳糖通过美拉德反应结合到胺化 MNP 的表面。通过将 MNP@LAC 与样品在室温下振荡孵育，然后进行磁隔离，蓖麻蛋白 B 的富集需要约 1 小时。所得的 MNP@LAC-蓖麻毒素 B 偶联物通过基质辅助激光解吸/电离质谱 (MALDI-MS) 进行表征。使用开发的方法对蓖麻毒蛋白 B 的检测限为~3 nM。可以检测由 MNP@LAC 探针富集的痕量蓖麻蛋白 B (~0.39 nM) 的胰蛋白酶消化衍生的肽，然后进行胰蛋白酶消化和 MALDI-MS 分析。

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