Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, 400715, Chongqing, P.R. China.
Analyst. 2018 Nov 19;143(23):5764-5770. doi: 10.1039/c8an01217b.
Ricin is an extremely potent ribosome-inactivating protein and serves as a likely food biocontaminant or biological weapon. Thus, simple, sensitive and accurate analytical assays capable of detecting ricin are urgently needed to be established. Herein, we present a novel method for ricin B-chain (RTB) detection by using two materials: (a) a highly efficient hybrid probe that was formed by linking a glucose oxidase (GOD)-encapsulated liposome (GOD-L) to magnetic beads (MBs) through hybridization between an aptamer and a blocker and (b) a new low-background g-C3N4-MnO2 sandwich nanocomposite that exhibits fluorescence resonance energy transfer (FRET) between the g-C3N4 nanosheet and MnO2. In the presence of RTB, the strong binding between RTB and the aptamer can release the blocker-linked liposome from the surface of the MBs. After magnetic separation, the decomposed liposome can release GOD to catalyze the oxidation of glucose, generating a certain amount of H2O2. Then, H2O2 can reduce MnO2 of the g-C3N4-MnO2 nanocomposite to Mn2+, which leads to the elimination of FRET. Thus, the fluorescence of the g-C3N4 nanosheet will be turned on. Because of the excellent signal amplification ability of liposome and the characteristic highly sensitive response of the g-C3N4-MnO2 nanocomposite toward H2O2, RTB could be detected sensitively based on the significantly enhanced fluorescent intensity. The linear range of detection was from 0.25 μg mL-1 to 50 μg mL-1 and the limit of detection (LOD) was 190 ng mL-1. Moreover, the proposed assay was successfully applied in the detection of the entire ricin toxin content in a castor seed.
蓖麻毒素是一种极其有效的核糖体失活蛋白，可能作为食物生物污染物或生物武器。因此，迫切需要建立能够检测蓖麻毒素的简单、灵敏和准确的分析方法。在此，我们提出了一种新的检测蓖麻毒素 B 链（RTB）的方法，该方法使用了两种材料：（a）一种高效的杂交探针，该探针通过将与适体和阻滞剂杂交的葡萄糖氧化酶（GOD）包封的脂质体（GOD-L）连接到磁性珠（MBs）上来形成；（b）一种新的低背景 g-C3N4-MnO2三明治纳米复合材料，该复合材料在 g-C3N4纳米片和 MnO2之间表现出荧光共振能量转移（FRET）。在 RTB 的存在下，RTB 与适体之间的强结合可以将连接阻滞剂的脂质体从 MBs 的表面释放出来。经过磁分离后，分解的脂质体可以释放 GOD 来催化葡萄糖的氧化，产生一定量的 H2O2。然后，H2O2可以将 g-C3N4-MnO2纳米复合材料中的 MnO2还原为 Mn2+，从而消除 FRET。因此，g-C3N4纳米片的荧光将被打开。由于脂质体具有出色的信号放大能力，以及 g-C3N4-MnO2纳米复合材料对 H2O2的特征高灵敏度响应，因此可以根据显著增强的荧光强度来灵敏地检测 RTB。检测范围从 0.25 μg mL-1 到 50 μg mL-1，检测限（LOD）为 190 ng mL-1。此外，该方法成功应用于蓖麻种子中整个蓖麻毒素含量的检测。
