School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian, 116024, China.
School of Bioengineering, Dalian University of Technology, Dalian, 116024, China.
Angew Chem Int Ed Engl. 2020 May 11;59(20):7706-7710. doi: 10.1002/anie.202000025. Epub 2020 Mar 24.
Protein biomarkers often exist as degradation fragments in biological samples, and affinity agents derived using a purified protein may not recognize them, limiting their value for clinical diagnosis. Herein, we present a method to overcome this issue, by selecting aptamers against a degraded form of the toxin B protein, which is a marker for diagnosing toxigenic Clostridium difficile infections. This approach has led to isolation of a DNA aptamer that recognizes degraded toxin B, fresh toxin B, and toxin B spiked into human stool samples. DNA aptamers selected using intact recombinant toxin B failed to recognize degraded toxin B, which is the form present in stored stool samples. Using this new aptamer, we produced a simple paper-based analytical device for colorimetric detection of toxin B in stool samples, or in the NAP1 strain of Clostridium difficile. The combined aptamer-selection and paper-sensing strategy can expand the practical utility of DNA aptamers in clinical diagnosis.
蛋白质生物标志物通常以生物样本中的降解片段形式存在，而使用纯化蛋白衍生的亲和试剂可能无法识别它们，从而限制了其在临床诊断中的价值。在此，我们提出了一种克服该问题的方法，即针对降解形式的毒素 B 蛋白选择适体，该蛋白是诊断产毒艰难梭菌感染的标志物。这种方法导致分离出一种 DNA 适体，该适体能识别降解的毒素 B、新鲜的毒素 B 以及掺入人粪便样本中的毒素 B。使用完整的重组毒素 B 筛选出的 DNA 适体无法识别存在于储存粪便样本中的降解毒素 B。我们使用这种新的适体，开发了一种简单的基于纸张的分析装置，用于比色法检测粪便样本中的毒素 B，或检测艰难梭菌 NAP1 株中的毒素 B。这种组合的适体选择和纸张感应策略可以扩大 DNA 适体在临床诊断中的实际应用。
