Photoelectrochemical aptasensor with low background noise

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ORIGINAL PAPER

Photoelectrochemical aptasensor with low background noise Yuchan Meng 1 & Shanshan Wang 1 & Jikuan Zhao 1 & Xu Hun 1 Received: 13 January 2020 / Accepted: 12 October 2020 # Springer-Verlag GmbH Austria, part of Springer Nature 2020

Abstract In photoelectrochemical (PEC) detection, enhancing the PEC signal and depressing the blank signal are conducive to improve the sensitivity. Because the carbon nanotube (CNT) effectively transfers photogenerated electrons from SnSe to the electrode, the composite nanomaterial CNTs/SnSe generates a strong PEC signal. Methionine (Met), AuNPs, and probe DNA are woven together forming a nanoprobe which is used as a quencher to quench the PEC signal of CNTs/SnSe. When the nanoprobe and CNTs/SnSe are modified onto the electrode, there is a low blank signal. In the presence of metastatic breast cancer cells, the cells interact with the aptamer of dsDNA; concomitantly, cDNA is released to trigger catalytic hairpin assembly (CHA). As a result, a new dsDNA which has an overhang is formed. The nanoprobe on the surface of the electrode hybridizes with the newly formed dsDNA. Subsequently, the nanoprobe is released from the surface of the electrode and the quenching effect between the nanoprobe and the CNTs/SnSe disappears. The PEC aptasensor is linear in the concentration range of 300–5,000 cells/mL, and the detection limit is 180 cells/mL under optimized conditions. The relative standard deviation (RSD) is 3.6% at 10,000 cells/ mL. This work demonstrates a promising strategy using CNTs/SnSe as the photoactive material and Met-AuNPs as the quencher to establish a PEC aptasensor with a high PEC response and low blank signal. It can be used to detect bioactive substances at ultralow levels prospectively. Keywords Fluorescence quencher . CNTs/SnSe . Cancer cell . Nanosheets . Methionine

Introduction Photoelectrochemical (PEC) analysis has received widespread attention due to the combination of the advantages of both the optical and electrochemical strategies [1]. The PEC method uses light and electricity energy for the sensor excitation and detection, respectively, thus enabling the efficient reduction of some undesired background noise and increasing the signalElectronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-020-04601-3) contains supplementary material, which is available to authorized users. * Xu Hun [email protected] 1

Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science, MOE, Shandong Key Laboratory of Biochemical Analysis, Key Laboratory of Analytical Chemistry for Life Science in Universities of Shandong, State Key Laboratory Base of Eco-chemical Engineering, Key Laboratory of Rubber-Plastics of Ministry of Education/Shandong Provincial Key Laboratory of Rubber Plastics, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China

to-noise ratio [2, 3]. For a PEC platform, photoactive materials are the vital part concerned with th