Ultrasensitive Photoelectrochemical Detection of MicroRNA on Paper by Combining a Cascade Nanozyme-Engineered Biocatalytic Precipitation Reaction and Target-Triggerable DNA Motor

Abstract

Developing efficient strategies for sensitive detection of microRNAs, the noncoding bioactive molecules and wellestablished biomarkers, has aroused great interests due to its great potential values in genetic and pathological analyses. Herein, a highly selective and disposable paper-based photoelectrochemical (PEC) sensor was rationally designed for sensing microRNA based on simple self-assembly of a target-triggerable DNA motor and nanozyme-catalyzed multistage biocatalytic precipitation reaction. Specifically, a brand-new type II heterojunction of TiO 2 −CeO 2 nanotubes decorated with carbon fiber paper (CFP) was first prepared, which gave an enhanced photoreactive surface and realized fast electron transport and extraction, markedly accelerating photoelectric conversion efficiency of the sensor. For achieving target detection, cascade nanozyme centers of the CeO 2 and Au nanoparticles modified by cyclodextrin were drafted, greatly decreasing the photocurrent intensity and achieving an ultralow background signal. With target introduction, the DNA motor was activated and automatically moved along the predesigned route driven by an endonuclease cleavage reaction, resulting in more substrate probe digestion and nanozyme release from CFP. Consequently, the repressive inner enhancement mechanism was gradually renewed with constant advancement of the enzymatic reaction and walker probe walking progressively, eventually allowing multiple enzymatic factor output in each target import. As a proof-of-concept application, the developed PEC sensor successfully performed detection of miRNA-141, showing a low detection limit of 0.6 fM, and was further applied to real sample bioassays with satisfying results. This work proposes promising strategies to boost the catalytic cascade DNA-motor adhibition in biological samples analysis and also exhibits potential capability in detection of other targets.

Nanostructured Ceria: Biomolecular Templates and (Bio)applications

“…Ceria NPs were used to develop sensors for lactate, whose levels can be diagnostic of various diseases [166]. ATP [167], microRNAs [168,169], and DNA [170] were successfully detected too using ceria, for cancer diagnostics [171] or forensics applications [172]. Sensors were developed to monitor the presence of drugs, such as sulfonamide [173] and omeprazole [174].…”

Advanced Signal-Amplification Strategies for Paper-Based Analytical Devices: A Comprehensive Review

“…Therefore, PEC-based signal amplification enhancement that can address these issues is necessary in order to minimize the number of assays, but still reach high sensitivity with a very low concentration. In the last few years, diverse strategies have been proposed to amplify photoactive signals for PEC-sensing fabrication, most of which have been employed in electron acceptor/donor regulation [ 120 , 123 , 124 , 125 , 126 ], photoactive materials, nanozymes [ 119 , 120 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 ], or light sources [ 136 , 137 , 138 , 139 , 140 , 141 , 142 ]. Among them, functional nanomaterial integration is an emerging potent route to reach giant, efficient lab-on-paper analytical devices, and diverse photoactive nanomaterials have been immobilized on cellulose fibers.…”

“…In photoactive material-associated PEC paper-based devices, photoactive species play an essential role serving as a light absorber [ 119 ]. In particular, emerging nanozymes are being intensively investigated as an expected alternative to natural enzymes due to their many intrinsic qualities, including superior stability, enzyme-like capabilities, and wide pH operating range [ 128 ]. For instance, Li and coworkers fabricated photoelectrochemical paper-based sensing to detect carcinoembryonic antigen (CEA) based on the modification of paper with N-carbon dots/TiO 2 –Pt in a seed-mediated growth method [ 144 ].…”

“…This novel platform has good biocompatibility, is portable, and has eco-friendly devices that can detect low levels in limitations of 1.0 pg mL –1 over a broad linear range of 0.002–200 ng mL –1 . Additionally, Li and colleagues also employed this strategy to develop an ultrasensitive PEC paper-based device to determine miRNA-141 from a two-enzyme-engineered DNA walker and a TiO 2 /CeO 2 heterojunction ( Figure 7 D) [ 128 ]. During cancer development, miRNA-141 is expressed in large proportions, and thus, acts as a potential marker for cancer diagnostics and assessment.…”

“…(D) An ultrasensitive PEC paper-based device to determine miRNA-141 from a two-enzyme-engineered DNA walker and a TiO2/CeO2 heterojunction. Adapted with permission from Ref [128]…”