We demonstrate for the first time a fast aptamer generation method based on the screen-printed electrodynamic microfluidic channel device, where a specific aptamer selectively binds to a target protein on channel walls, following recovery and separation. A malaria protein as a model target, Plasmodium vivax lactate dehydrogenase (PvLDH) was covalently bonded to the conductive polymer layer formed on the carbon channel walls to react with the DNA library in a fluid. Then, the AC electric field was symmetrically applied on the channel walls for inducing the specific binding of the target protein to DNA library molecules. In this case, the partitioning efficiency between PvLDH and DNA library in the channel was attained to be 1.67 × 10⁷ with the background of 5.56 × 10^–6, which was confirmed using the quantitative polymerase chain reaction (qPCR). The selectively captured DNAs were isolated from the protein and separated in situ to give five aptamers with different sequences by one round cycle. The dissociation constants (K_d) of the selected aptamers were determined employing both electrochemical impedance spectroscopy (EIS) and the fluorescence method. The sensing performance of each aptamer was evaluated for the PvLDH detection after individual immobilization on the screen-printed array electrodes. The most sensitive aptamer revealed a detection limit of 7.8 ± 0.4 fM. The sensor reliability was evaluated by comparing it with other malaria sensors.

中文翻译：

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基于电动微流体通道的快速适体生成方法及适体传感器性能评估

我们首次展示了一种基于丝网印刷的电动微流体通道装置的快速适体生成方法，其中一种特定的适体在回收和分离后选择性地结合至通道壁上的靶蛋白。间日疟原虫乳酸脱氢酶（PvLDH）是疟疾的模型目标，它与碳通道壁上形成的导电聚合物层共价键合，从而与液体中的DNA文库反应。然后，将交流电场对称地施加在通道壁上，以诱导靶蛋白与DNA文库分子的特异性结合。在这种情况下，通道中PvLDH和DNA文库之间的分配效率为1.67×10 ⁷，背景为5.56×10 ^–6，使用定量聚合酶链反应（qPCR）进行了确认。从蛋白质中分离出选择性捕获的DNA，并在原位分离，通过一个回合循环得到五个具有不同序列的适体。使用电化学阻抗谱（EIS）和荧光方法确定所选适体的解离常数（K _d）。分别固定在丝网印刷的阵列电极上后，针对PvLDH检测评估每个适体的传感性能。最敏感的适体显示出7.8±0.4 fM的检测极限。通过与其他疟疾传感器进行比较来评估传感器的可靠性。