In this work, the manganese porphyrin (MnPP) decorated on DNA networks could serve as quencher and mimicking enzyme to efficiently reduce the photocurrent of photoactive material 3,4,9,10-perylene tetracarboxylic acid (PTCA), which was elaborately used to construct a novel label-free aptasensor for ultrasensitive detection of thrombin (TB) in a signal-off manner. The Au-doped PTCA (PTCA-PEI-Au) with outstanding membrane-forming and photoelectric property was modified on electrode to acquire a strong initial photoelectrochemistry (PEC) signal. Afterward, target binding aptamer Ι (TBAΙ) was modified on electrode to specially recognize target TB, which could further combine with TBAII and single-stranded DNA P1-modified platinum nanoparticles (TBAII-PtNPs-P1) for immobilizing DNA networks with abundant MnPP. Ingeniously, the MnPP could not only directly quench the photocurrent of PTCA, but also acted as hydrogen peroxide (HRP) mimicking enzyme to remarkably stimulate the deposition of benzo-4-chlorhexidine (4-CD) on electrode for further decreasing the photocurrent of PTCA, thereby obtaining a definitely low photocurrent for detection of TB. As a result, the proposed PEC aptasensor illustrated excellent sensitivity with a low detection limit down to 3 fM, exploiting a new avenue about intergrating two functions in one substance for ultrasensitive biological monitoring.

在这项工作中，在DNA网络上装饰的锰卟啉（MnPP）可以用作淬灭剂和模拟酶，以有效降低光敏材料3,4,9,10- tetra四甲酸（PTCA）的光电流，该光敏材料被精心地用于构建一种新颖的无标记适体传感器，用于以信号关闭方式超灵敏地检测凝血酶（TB）。在电极上修饰具有出色的成膜性和光电性能的金掺杂PTCA（PTCA-PEI-Au），以获取强的初始光电化学（PEC）信号。之后，在电极上修饰靶结合适体I（TBA1）以特异性识别靶TB，其可以进一步与TBAII和单链DNA P1修饰的铂纳米颗粒（TBAII-PtNPs-P1）结合以固定具有丰富的MnPP的DNA网络。巧妙地 MnPP不仅可以直接淬灭PTCA的光电流，而且还可以作为过氧化氢（HRP）模拟酶，显着刺激苯并4-氯己定（4-CD）在电极上的沉积，从而进一步降低PTCA的光电流。获得绝对低的光电流用于结核病的检测。结果，提出的PEC适体传感器显示出极佳的灵敏度，低至3 fM的低检测限，为将两种功能整合在一种物质中进行了超灵敏的生物监测开辟了一条新途径。