A split G-quadruplex-based DNA nano-tweezers structure as a signal-transducing molecule for the homogeneous detection of specific nucleic acids

• Published in: Biosensors & bioelectronics Vol. 74; pp. 222 - 226
• Main Authors: Nakatsuka, Keisuke, Shigeto, Hajime, Kuroda, Akio, Funabashi, Hisakage
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.12.2015
• Subjects: Biosensing Techniques - methods; Biosensors; Caliciviridae Infections - virology; Colorimetry - methods; Deoxyribonucleic acid; Devices; DNA, Single-Stranded - chemistry; G-Quadruplexes; Homogeneous assay; Humans; Limit of Detection; Nanostructure; Norovirus; Norovirus - isolation & purification; Nucleic acid detection; Nucleic acids; Peroxidase; Point-of-Care Systems; Point-of-care testing; Portability; RNA, Viral - analysis; Signal-transducing molecule; Split G-quadruplex; Target recognition; Point-of-care testing; Homogeneous assay; Norovirus; Split G-quadruplex; Signal-transducing molecule; Nucleic acid detection
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.06.055

A portable method of specific nucleic acid detection would be very useful for monitoring public health in a variety of settings for point-of-care and point-of-need testing. However, conventional methods for the detection of nucleic acids are not ideal for use in the field, as they require skilled operators and complex equipment. Here, we constructed a method for specific nucleic acid detection using a split G-quadruplex (Gq) structure that can recognize target nucleic acids without competitive reactions in a bimolecular reaction and directly produce a detectable signal based on peroxidase activity. We developed a single signal-transducing molecule with a split Gq-based DNA-nano tweezers (NT) structure that self-assembles from three single-stranded DNAs through simple mixing, and detects its target without requiring any washing steps. A model target, a partial norovirus mRNA (NV-RNA), was specifically recognized by the split Gq-based DNA-NT, causing it to undergo a structural change that restored its peroxidase activity. The peroxidase activity was measured by following the oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), which gave a greenish colorimetric response, and was proportional to the NV-RNA concentration. The lower detection limit was 4nM. Our results demonstrated the feasibility of detecting specific nucleic acids with a split Gq-based DNA-NT structure as a nucleic acid signal-transducing molecule in a homogenous assay format. Also the target recognition sites of split Gq-based DNA-NT can easily be designed without delicate optimization of tweezers structure. Thus a split Gq-based DNA-NT technique is readily applicable to a basic platform for the development of a portable device. •A split G-quadruplex (Gq)-based DNA nano-tweezers (NT) structure was designed.•The DNA-NT was created by the self-assembly of three single-stranded DNAs.•The DNA-NT exhibited peroxidase activity in response to a target RNA model.•The colorimetric detection of the target RNA was performed in a homogeneous assay.