Dual near‐infrared AgInS <sub>2</sub> and CuInS <sub>2</sub> co‐sensitized ZnO photoelectrode array enabled paper‐based ratiometric photoelectrochemical aptasensing
Hongmei Yang, Chuanyi Tu, Yilin Zhuang, Yuheng Li, Yuxin Hao, Qiuyi Li, Lina Zhang, Jinghua Yu, Yan Zhang
Abstract
Abstract Herein, a dual near‐infrared (NIR)‐response AgInS 2 and CuInS 2 co‐sensitized ZnO photoelectrode array consisting of two spatial‐resolved paper working electrodes (PWE 1 and PWE 2 ) was established to enable paper‐based ratiometric photoelectrochemical (PEC) aptasensing of Di(2‐ethylhexyl)phthalate (DEHP) based on triple‐helix molecular switch (THMS)‐mediated “on–off” switching of co‐sensitization effect. Profiting from the co‐sensitization of AgInS 2 and CuInS 2 on paper‐based ZnO, the dual NIR‐response cascade sensitization structure of AgInS 2 /CuInS 2 /ZnO exhibited a wide light response range and high charge separation efficiency, giving a “switch on” state of co‐sensitization effect with markedly high photocurrent response. The “switch off” state of the co‐sensitization effect was made by RecJf exonuclease‐assisted target recycling‐induced conformation change of THMS, which caused the detachment of AgInS 2 quantum dots from the aptasensing interface, leading to a significantly decreased photocurrent signal. Accordingly, the constant I 1 of PWE 1 and varying I 2 of PWE 2 were collected based on the incubation of constant concentration of DEHP on PWE 1 and various concentrations of DEHP on PWE 2 . The ultrasensitive detection of DEHP was realized by calculating the ratio of I 2 / I 1 . This work brought new insights into the establishment of a high‐performance paper‐based ratiometric PEC aptasensing platform for highly sensitive quantification of DEHP.