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In Vitro Selection of a DNA Aptamer Targeting Degraded Protein Fragments for Biosensing
Author(s) -
Liu Meng,
Wang Jiayi,
Chang Yangyang,
Zhang Qiang,
Chang Dingran,
Hui Christy Y.,
Brennan John D.,
Li Yingfu
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202000025
Subject(s) - aptamer , toxin , systematic evolution of ligands by exponential enrichment , clostridium difficile , recombinant dna , clostridium difficile toxin b , dna , biology , clostridium difficile toxin a , microbiology and biotechnology , computational biology , chemistry , biochemistry , gene , rna , antibiotics
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.