Wu Peng, Pan Jian-Bing, Li Xiang-Ling, Hou Xiandeng, Xu Jing-Juan, Chen Hong-Yuan
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Analytical & Testing Center, Sichuan University, Chengdu 610064 (China).
Chemistry. 2015 Mar 23;21(13):5129-35. doi: 10.1002/chem.201405798. Epub 2015 Feb 12.
Photoelectrochemical (PEC) biosensing with semiconductor quantum dots (QDs) has received great attention because it integrates the advantages of both photo-excitation and electrochemical detection. During the photon-to-electricity conversion in PEC processes, electron-hole (charge) separation competes with electron-hole recombination, and the net effect essentially determines the performance of PEC biosensors. Herein, we propose a new approach for slowing down electron-hole recombination to increase charge separation efficiency for PEC biosensor development. Through doping with Mn(2+) , a pair of d bands ((4) T1 and (6) A1 ) is inserted between the conduction and valence bands of CdS QDs, which alters the electron-hole separation and recombination dynamics, allowing the generation of long-lived charge carriers with ms-scale lifetime that decay about 10(4) -10(5) -fold more slowly than in the case of undoped QDs. Photocurrent tests indicated that Mn(2+) doping resulted in an approximately 80 % increase in photocurrent generation compared with undoped CdS QDs. For application, the Mn-doped CdS QDs were coated on the surface of a glassy carbon electrode and functionalized with a cell surface carbohydrate-specific ligand (3-aminophenylboronic acid). In this way, a sensitive cytosensor for K562 leukemia cells was constructed. Moreover, the sugar-specific binding property of 3-aminophenylboronic acid allowed the electrode to serve as a switch for the capture and release of cells. This has been further explored with a view to developing a reusable PEC cytosensing platform.
基于半导体量子点（QDs）的光电化学（PEC）生物传感因其兼具光激发和电化学检测的优势而备受关注。在PEC过程的光子到电子转换过程中，电子-空穴（电荷）分离与电子-空穴复合相互竞争，其净效应本质上决定了PEC生物传感器的性能。在此，我们提出一种新方法来减缓电子-空穴复合，以提高电荷分离效率，用于PEC生物传感器的开发。通过用Mn(2+) 掺杂，在CdS量子点的导带和价带之间插入一对d带（(4) T1和(6) A1 ），这改变了电子-空穴分离和复合动力学，使得能够产生具有毫秒级寿命的长寿命电荷载流子，其衰减速度比未掺杂量子点的情况慢约10(4) -10(5) 倍。光电流测试表明，与未掺杂的CdS量子点相比，Mn(2+) 掺杂导致光电流产生增加了约80％。为了应用，将Mn掺杂的CdS量子点涂覆在玻碳电极表面，并用细胞表面碳水化合物特异性配体（3-氨基苯硼酸）进行功能化。通过这种方式，构建了一种用于K562白血病细胞的灵敏细胞传感器。此外，3-氨基苯硼酸的糖特异性结合特性使电极能够作为细胞捕获和释放的开关。为了开发可重复使用的PEC细胞传感平台，对此进行了进一步探索。
