State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P R China.
Anal Chem. 2011 Mar 1;83(5):1523-9. doi: 10.1021/ac101988n. Epub 2011 Feb 3.
Aptamers are artificial oligonucleotides that have been widely employed to design biosensors (i.e., aptasensors). In this work, we report a microfluidic electrochemical aptamer-based sensor (MECAS) by constructing Au-Ag dual-metal array three-electrode on-chip for multiplex detection of small molecules. In combination with the microfluidic channels covering on the glass chip, different targets are transported to the Au electrodes integrated on different positions of the chip. These electrodes are premodified by different kinds of aptamers, respectively, to fabricate different sensing interfaces which can selectively capture the corresponding target. It is an address-dependent sensing platform; thus, with the use of only one electrochemical probe, multitargets can be recognized and detected according to the readout on a corresponding aptamer-modified electrode. In the sensing strategy, the electrochemical probe, Ru(NH(3))(6) (RuHex), which can quantitatively bind to surface-confined DNA via electrostatic interaction, was used to produce chronocoulometric signal; Au nanoparticles (AuNPs) were used to improve the sensitivity of the sensor by amplifying the detection signals. Moreover, the sensing interface fabrication, sample incubation, and electrochemical detection were all performed in microfluidic channels. By using this detection chip, we achieved the multianalysis of two model small molecules, ATP, and cocaine, in mixed samples within 40 min. The detection limit of ATP was 3 × 10(-10) M, whereas the detection limit of cocaine was 7 × 10(-8) M. This Au-Ag dual metal electrochemical chip detector integrated MECAS was simple, sensitive, and selective. Also it is similar to a dosimeter which accumulates signal upon exposure. It held promising potential for designing electrochemical devices with high throughput, high automation, and high integration in multianalysis.
适体是一种人工合成的寡核苷酸，已广泛用于生物传感器（即适体传感器）的设计。在这项工作中，我们报告了一种基于微流控电化学适体的传感器（MECAS），通过在芯片上构建 Au-Ag 双金属阵列三电极用于小分子的多重检测。结合覆盖在玻璃芯片上的微流道，不同的靶标被输送到芯片不同位置集成的 Au 电极。这些电极分别通过不同种类的适体进行预修饰，以制备不同的传感界面，这些界面可以选择性地捕获相应的靶标。这是一种基于地址的传感平台；因此，只需使用一个电化学探针，就可以根据对应适体修饰电极上的读出结果识别和检测多个靶标。在传感策略中，使用电化学探针Ru(NH(3))(6)（RuHex），它可以通过静电相互作用定量结合到表面受限的 DNA 上，产生计时库仑信号；金纳米粒子（AuNPs）用于通过放大检测信号来提高传感器的灵敏度。此外，传感界面的制备、样品孵育和电化学检测都在微流道中进行。通过使用这种检测芯片，我们在 40 分钟内实现了两种模型小分子 ATP 和可卡因在混合样品中的多分析。ATP 的检测限为 3×10(-10) M，而可卡因的检测限为 7×10(-8) M。这种 Au-Ag 双金属电化学芯片检测器集成了 MECAS，具有简单、灵敏和选择性。它也类似于一种剂量计，在暴露时会累积信号。它在高通量、高自动化和高集成度的多分析电化学器件设计方面具有广阔的应用前景。
