Photoelectrochemical Biosensor for MicroRNA-21 Based on High Photocurrent of TiO2/Two-Dimensional Coordination Polymer CuClx(MBA)y Photoelectrode.
Photoelectrochemical Biosensor for MicroRNA-21 Based on High Photocurrent of TiO2/Two-Dimensional Coordination Polymer CuClx(MBA)y Photoelectrode.
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DOI：
10.1021/acs.analchem.1c02267
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发表时间：
2021-07
影响因子：
7.4
通讯作者：
Jiao Yang;Yanzhou Li;Longhua Guo;Bin Qiu;Zhenyu Lin
中科院分区：
文献类型：
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作者：
Jiao Yang;Yanzhou Li;Longhua Guo;Bin Qiu;Zhenyu Lin
传统的光敏材料如TiO 2在紫外区吸收受限、光生电子-空穴对快速复合以及缺乏用于生物耦合的官能团，这些都阻碍了它们在光电化学（PEC）生物传感中的应用。本文设计并合成了一种新的基于Cu（I）、氯离子和4-巯基苯甲酸（MBA）的配位聚合物（简称CuClx（MBA）y）。制备的p型CuClx（MBA）y由于其窄的光学带隙（2.59 eV）而表现出可见光吸收，并且其适当的带边位置使其能够与TiO 2形成p-n结。通过层层组装，CuClx（MBA）y/TiO 2/FTO复合光电极的光电流强度是TiO 2/FTO电极的3.7倍，是CuClx（MBA）y/FTO电极的35倍。探讨了CuClx（MBA）y增强TiO 2可见光吸收和促进TiO 2 p-n结电子空穴对分离的可能机制。此外，CuClx（MBA）y纳米片由于含有丰富的羧基，可以直接实现生物结合.将CuClx（MBA）y/TiO 2/FTO复合光电极应用于microRNA-21（模型靶）的PEC生物传感器。通过巧妙地利用CuClx（MBA）y和Au纳米颗粒（AuNPs）之间的能量传递，AuNPs充当有效的猝灭剂。在靶的存在下，AuNP标记的sDNA 1连接到电极表面，因此，获得降低的光电流。该传感器具有较低的检测限为0.29 fM（S/N = 3），良好的选择性和重现性。将该系统应用于癌细胞中microRNA的检测，结果令人满意。
Conventional photosensitive materials such as TiO2 suffer from restricted absorption in the ultraviolet region, fast recombination of photogenerated electron-hole pairs, and a lack of functional groups for biocoupling, which hinder their application in photoelectrochemical (PEC) biosensing. Herein, a new coordination polymer (CP) based on Cu(I), chloridion, and 4-mercaptobenzoic acid (MBA) has been designed and synthesized (called CuClx(MBA)y). The prepared p-type CuClx(MBA)y exhibits visible-light absorption due to its narrow optical band gap (2.59 eV), and its proper band edge position enables it to form a p-n junction with TiO2. Through layer-by-layer assembling, the photocurrent intensity of the CuClx(MBA)y/TiO2/FTO composite photoelectrode was 3.7-fold higher than that of a TiO2/FTO electrode and 35-fold higher than a CuClx(MBA)y/FTO electrode. The potential enhancement mechanism was discussed, which lies in the contributions of CuClx(MBA)y in enhancing absorption in the visible-light region and boosting the separation of electron-hole pairs of TiO2 by the p-n junction. Furthermore, CuClx(MBA)y nanosheets can realize bioconjugation directly, thanks to its abundant carboxyl groups. The CuClx(MBA)y/TiO2/FTO composite photoelectrodes were applied to develop a sensitive PEC biosensor for microRNA-21 (model target). By subtly exploiting the energy transfer between CuClx(MBA)y and Au nanoparticles (AuNPs), AuNPs served as effective quenchers. In the presence of the target, AuNP-labeled sDNA1 connected to the electrode surface, and thus, a decreased photocurrent was obtained. The proposed biosensor has a low detection limit of 0.29 fM (S/N = 3), good selectivity, and reproducibility. The proposed system was applied to monitor microRNA in cancer cells with satisfying results.