Microporous Luminescent Metal–Organic Framework for a Sensitive and Selective Fluorescence Sensing of Toxic Mycotoxin in Moldy Sugarcane

Food contamination by toxic mycotoxins not only causes a considerable loss in economy, but importantly poses a huge threat to human health through accidental ingestion. Hence, it is an ongoing and imperative need to develop a convenient, cost-effective method for the detection of the mycotoxin-infected agricultural commodities. To this end, we herein fabricated a novel metal–organic framework-derived composite material that displays a strong solid-state emission in the visible region, by attaching a frequently used fluorescent label, fluorescein isothiocyanate (FITC), via guest adsorption. Significantly, owing to the inherent pH-responsive conformational changes of FITC, the resulting composite material provides, to the best of our knowledge, the first example of the sensitive and selective fluorescence sensing toward 3-nitropropionic acid, which, as a major naturally occurring mycotoxin in moldy sugarcane, has been closely linked to poisoning episodes in human beings and animals.

有毒真菌毒素（mycotoxin）污染食品不仅会造成显著的经济损失，更重要的是，人类误食受污染食品后会对健康构成巨大威胁。因此，开发便捷、经济高效的真菌毒素污染农产品检测方法是一项持续且紧迫的需求。为此，本研究通过客体吸附的方式将常用荧光标记物异硫氰酸荧光素（fluorescein isothiocyanate, FITC）负载于材料表面，制备了一种在可见光区域具有强固态发射特性的新型金属有机框架衍生复合材料（metal–organic framework-derived composite material）。值得注意的是，鉴于异硫氰酸荧光素固有的pH响应构象变化，据我们所知，所制备的复合材料首次实现了对3-硝基丙酸（3-nitropropionic acid）的高灵敏、高选择性荧光传感。3-硝基丙酸是霉变甘蔗中天然存在的主要真菌毒素，与人类和动物的中毒事件密切相关。