LAUSR

In this work, boronic acid-aptamer conjugate (BAAC) is elaborately designed and explored as recognition unit. The admirable property of the pH-dependent boronic acid ester is integrated with the specific capturing capability of the modified aptamer, thus BAAC can efficiently and selectively bind with target by adjusting pH values. An electrochemical biosensor based on pH-adjusted BAAC has been further developed for analysis of CNeu5Gc, an important biomarker of different kinds of cancer. The boronic acid moiety in BAAC can react with CNeu5Gc to form BAAC-CNeu5Gc complex under acidic condition, followed by release of CNeu5Gc from the complex and subsequent capture by aptamer moiety with adjustment of pH value to alkalinity. With simplicity, high specificity and efficiency, the biosensor exhibits the wide linear range from 2.816 ng/mL to 3603.960 ng/mL with low detection limit of 1.224 ng/mL and can be applied to analyze CNeu5Gc in animal food samples. Besides, this work can also provide one kind of modified aptamer, i.e. chemical capturing group modified aptamer, to give a new viewpoint for exploration of other functionalized aptamers.