A Ratiometric Fluorescent DNA Radar Based on Contrary Response of DNA/Silver Nanoclusters and G-Quadruplex/Crystal Violet

Abstract

G-quadruplex (G4) exhibits infinite application foreground due to its special properties and critical roles in biological regulation. A DNA radar was first built by assigning the silver nanocluster (AgNC) as the radar transmitter, the middle single strand DNA-bridge connected on the AgNCs as the electromagnetic wave, and the G4/crystal violet complex as the radar antenna. The radar antenna could receive the signal of the target DNA that met the electromagnetic wave and give a location via light-up fluorescence. Here, G4 is chosen as the suitable template to connect potential nanomaterial AgNCs with the G4 binder (crystal violet, CV) since the rich guanine in G4 could not only enhance the fluorescence of AgNCs but also form quartets offering powerful binding sites for the G4 binder. Meanwhile, the hybridization behavior of the middle single strand-bridge produced contrary effects decreasing the fluorescence of AgNCs and increasing the fluorescence of G4/CV, which vests a ratiometric feature in such DNA radar. Additionally, this DNA radar model could realize a cascade of logic circuits, the construction of a 1-to-2 decoder, and the ratiometric detection of target DNA. This system could also be employed for DNA detection in a biological matrix, which could be potentially usable as a unique means for monitoring the pathological process of disease, and lays the foundation for the future treatment of diseases.

DNA-Grafted 3D Superlattice Self-Assembly

“…The potential applications of these complex system turn to be of importance and attracts a lot of attention. For instance, DNA origami-based nanostructures were employed in biosensor [ 48 , 49 , 50 , 51 ], biocomputing [ 52 , 53 , 54 , 55 ], biomedicine [ 56 ] fields. Recently, DNA origami-guided 3D lattice engineering of inorganic NPs became one of the research hotspots.…”

DNA Origami-Enabled Biosensors

“…Fluorescent method is a powerful tool for sensing devices due to its quick response, high sensitivity, low abundance of sample, and simple operation. Metrics in technique promote its development in relevant areas such as synthesizing organic fluorescent ligands with stronger binding force and selectivity for structure [59][60][61], synthesizing fluorescent NPs with higher quantum yields [62][63][64][65], exploring new signal transduction mechanism among different fluorescent materials [66][67][68][69][70], and so on. Fluorescent ligands, NPs and signal transduction mechanism mentioned above were widely employed in studying conformational changes [71,72], monitoring drug release [73][74][75][76], and simulating the information communication among cells [77,78].…”

Antibody-Responsive Ratiometric Fluorescence Biosensing of Biemissive Silver Nanoclusters Wrapped in Switchable DNA Tweezers

“…To produce a target-dependent fluorescence signal of AgNCs with applicable emission from blue to red, − it is possibly crucial and yet challenging for the subtle design and assembly of DNA mechanical structures tethering cluster-nucleated templates, also including the modification of recognizable molecules. So far, much progress has been made to aim at the controllable regulation of the binding-induced fluorescence variation, such as exploring the ratio-type signal of color-altering and temperature-sensitive AgNCs. − Fascinatingly, dark or weak AgNCs were reported to be significantly lighted up by the proximal guanine (G)-rich DNA segments, even harvesting exponentially enhanced emission intensity. − Theoretically, this unique performance might attribute to a proposed mechanism of the Förster energy and/or electron transfer to AgNCs from G-rich sequences preferably adopting a compact secondary structure, i.e., G-quadruplex . As predicted, this signal transduction principle is applicable for ratiometric sensing systems in an emission-switchable or light-up manner, where AgNC templates and G-rich tails are directionally intercalated in the modifiable sites of functional self-assembled DNA nanomachines, such as DNA tweezers possessing rich mechanical properties.…”