Multiple self-cleaning paper-based electrochemical ratiometric biosensor based on the inner reference probe and exonuclease III-assisted signal amplification strategy

Publication date: Available online 9 October 2019Source: Biosensors and BioelectronicsAuthor(s): Xiaoxiao Zheng, Li Li, Lina Zhang, Li Xie, Xianrang Song, Jinghua YuAbstractRapid and accurate detection of nucleic acids plays a major role in biological research and clinical diagnostics. Here, a 3D multiple self-cleaning electrochemical ratiometric microfluidic paper-based analytical device (SER-μPAD) has been constructed for manganese super oxide dismutase (MnSOD) gene detection on the basis of the inner reference probe and exonuclease Ш (Exo Ш)-assisted analytes recycling amplification method. To simplify manual operations, a multipath self-cleaning tab that could manipulate fluid transport was introduced into the paper-based device, realizing time-programmable self-cleaning of the electrode. For achieving sensitive detection of MnSOD gene, the methylene blue (MB)-modified capture probe (CP) as the inner reference element was first self-assembled on triangular Au nanosheets modified paper working electrode to provide a built-in correction and improve the detection accuracy. When MnSOD gene existed, it hybridized with the hairpin-structured signal probe, triggering the cyclic amplification with the assistance of Exo Ш selective digestion to engender numerous residual DNA labeled with ferrocene (Fc) that could be captured on electrode surface by CPs. Hence, the Fc tags were close to the electrode surface, resulting in the oxidation peak current of Fc (IFc) increase, while t...
Source: Biosensors and Bioelectronics - Category: Biotechnology Source Type: research