Svigelj Rossella, Dossi Nicolo, Pizzolato Stefania, Toniolo Rosanna, Miranda-Castro Rebeca, de-Los-Santos-Álvarez Noemí, Lobo-Castañón María Jesús
Department of Agrifood, Environmental and Animal Science, University of Udine, Italy.
Department of Agrifood, Environmental and Animal Science, University of Udine, Italy.
Biosens Bioelectron. 2020 Oct 1;165:112339. doi: 10.1016/j.bios.2020.112339. Epub 2020 Jun 4.
Enzyme-linked immunosorbent assays are currently the most popular methods to quantify gluten in foods. Unfortunately, the antibodies used as specific receptors in such methods are not compatible with the usual solvents for the extraction of gluten proteins. In consequence, commercial tests require a high dilution of the sample after the extraction, increasing the limit of quantification and decreasing convenience. In this work, we have rationally truncated an aptamer capable of recognizing gliadin in a deep eutectic solvent (DES). The truncated aptamer is a 19-nucleotides-long DNA that minimizes self-hybridization, allowing the development of an electrochemical sandwich-based sensor for the quantification of gluten in the DES ethaline. The sensor incorporates two identical biotin-labeled truncated aptamers, one of which is immobilized on a carbon screen-printed electrode and the other reports the binding of gliadin after incubation in streptavidin-peroxidase. This sensor can detect gliadin in DES, with a dynamic range between 1 and 100 μg/L and an intra-assay coefficient of variation of 11%. This analytical performance allows the quantification of 20 μg of gluten/kg of food when 1 g of food is extracted with 10 mL of ethaline. We demonstrate the ability of this method to achieve the measurement of gluten in food samples, after the extraction with pure ethaline. The assay is useful for the analysis of residual gluten levels in foods, thus facilitating the evaluation of any potential health risk associated with the consumption of such food by people with celiac disease or other gluten-related disorders.
酶联免疫吸附测定法是目前定量食品中麸质最常用的方法。不幸的是，此类方法中用作特异性受体的抗体与麸质蛋白提取常用的溶剂不兼容。因此，商业检测需要在提取后对样品进行高度稀释，这增加了定量限并降低了便利性。在这项工作中，我们合理地截短了一种能够在深共熔溶剂（DES）中识别麦醇溶蛋白的适体。截短的适体是一条19个核苷酸长的DNA，可将自身杂交降至最低，从而开发出一种基于电化学夹心的传感器，用于定量DES乙胺中的麸质。该传感器包含两个相同的生物素标记截短适体，其中一个固定在碳丝网印刷电极上，另一个在与链霉亲和素 - 过氧化物酶孵育后报告麦醇溶蛋白的结合情况。该传感器能够检测DES中的麦醇溶蛋白，动态范围为1至100μg/L，测定内变异系数为11%。当用10mL乙胺提取1g食物时，这种分析性能允许定量20μg麸质/千克食物。我们证明了该方法在用纯乙胺提取后能够实现食品样品中麸质的测量。该测定法对于分析食品中的残留麸质水平很有用，从而有助于评估患有乳糜泻或其他麸质相关疾病的人食用此类食品可能存在的任何健康风险。
