Saxitoxin (STX), which is produced by certain dinoflagellate species, is a type of paralytic shellfish poisoning toxin that poses a serious threat to human health and the environment. Therefore, developing a technology for the convenient and cost-effective detection of STX is imperative. In this study, we developed an affinity peptide-imprinted polymer-based indirect competitive ELISA (ic-ELISA) without using enzyme–toxin conjugates. AuNP/CoO@Mg/Al cLDH was synthesized by calcining AuNP/ZIF-67@Mg/Al LDH, which was obtained by combining AuNPs, ZIF-67, and flower-like Mg/Al LDH. This synthesized nanozyme exhibited high catalytic activity ( = 0.24 mM for TMB and 132.5 mM for HO). The affinity peptide-imprinted polymer (MIP) was imprinted with an STX-specific template peptide (STX MIP) on a multi-well microplate and then reacted with an STX-specific signal peptide (STX SP). The interaction between the STX SP and MIP was detected using a streptavidin-coated nanozyme (SA-AuNP/CoO@Mg/Al cLDH). The developed MIP-based ic-ELISA exhibited excellent selectivity and sensitivity, with a limit of detection of 3.17 ng/mL (equivalent: 0.317 μg/g). Furthermore, the system was validated using a commercial ELISA kit and mussel tissue samples, and it demonstrated a high STX recovery with a low coefficient of variation. These results imply that the developed ic-ELISA can be used to detect STX in real samples.

中文翻译：

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纳米酶辅助分子印迹聚合物间接竞争ELISA检测海洋生物毒素

石房蛤毒素（STX）由某些甲藻产生，是一种麻痹性贝类中毒毒素，对人类健康和环境构成严重威胁。因此，开发一种方便且经济有效的 STX 检测技术势在必行。在本研究中，我们开发了一种基于亲和肽印迹聚合物的间接竞争 ELISA (ic-ELISA)，无需使用酶-毒素缀合物。 AuNP/CoO@Mg/Al cLDH通过煅烧AuNP/ZIF-67@Mg/Al LDH合成，AuNP/ZIF-67@Mg/Al LDH是由AuNPs、ZIF-67和花状Mg/Al LDH组合而成。这种合成的纳米酶表现出高催化活性（TMB = 0.24 mM，H2O = 132.5 mM）。亲和肽印迹聚合物（MIP）在多孔微孔板上印有STX特异性模板肽（STX MIP），然后与STX特异性信号肽（STX SP）反应。使用链霉亲和素包被的纳米酶 (SA-AuNP/CoO@Mg/Al cLDH) 检测 STX SP 和 MIP 之间的相互作用。开发的基于 MIP 的 ic-ELISA 表现出优异的选择性和灵敏度，检测限为 3.17 ng/mL（相当于：0.317 μg/g）。此外，该系统使用商业 ELISA 试剂盒和贻贝组织样本进行了验证，并显示出较高的 STX 回收率和较低的变异系数。这些结果表明所开发的 ic-ELISA 可用于检测实际样品中的 STX。