Versatile G-quadruplex-mediated strategies in label-free biosensors and logic systems

Abstract

G-quadruplex (G4), as one of the significant functional nucleic acids (FNAs), has attracted researchers' wide attention, and in particular has been employed for the construction of label-free molecular sensors and logic systems based on the peroxidase-like activity of the G4-hemin complex and G4-enhanced luminescence of G4-binding organic dyes. Its cation-dependent conformation and stability provide opportunities for the recognition of metal ion inputs and application of a split G4 strategy. Moreover, coupling the G4 sequence with other FNAs, e.g. metal ion-dependent DNAzymes and aptamers, has prominently broadened the range of possible targets from metal ions and DNA to diverse proteins and cells. Although there are limitations, such as a low ability of anti-interference and multiplex analysis, the excellent advantages (e.g. simplicity and low cost) endow the G4-mediated strategy with tremendous potential to be further exploited for practical bioanalysis and complicated DNA computing.

Recent Developments in G-Quadruplex Probes

“…Finally, we highlight recent examples of G-quadruplex small-molecule probes that have been used as G-quadruplex DNA imaging agents in living cells. Here, we focus mainly on examples that have been described in the last few years, as previous reviews on G-quadruplex probes describing earlier developments have been published by our group and others (Neo et al, 2012;Largy et al, 2013;Ren et al, 2015;Ruttkay-Nedecky et al, 2013;Vummidi et al, 2013). For ease of access, a summary of the photophysical properties of the G-quadruplex probes highlighted in this review can be found in Table 1.…”

Recent Advancements in Nanobioassays and Nanobiosensors for Foodborne Pathogenic Bacteria Detection

“…Incorporating nanoparticles in the assay serves to dramatically increase the surface area on which color precursor molecules may be docked. The AuNP-based G-quadruplex (quadruple-stranded DNA) enhances the luminescence of certain organic dyes in the presence of hemin (86). Based on this finding, Luo et al (72) introduced a AuNP colorimetric assay for the Salmonella invA gene.…”

A DNA Switch for Detecting Single Nucleotide Polymorphism within a Long DNA Sequence Under Denaturing Conditions

“…They can catalyze the oxidation of dyes such as 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) in the presence of hemin and hydrogen peroxide, which produces a color change (Figure B). This activity is known as peroxidase activity, and therefore, these types of DNA molecules are also called peroxidase DNAzymes . They can also bind to certain fluorogenic molecules, such as protoporphyrin IX (PPIX), to produce a strong fluorescence signal (Figure C) .…”

“…This activity is known as peroxidase activity,a nd therefore, theset ypes of DNA molecules are also called peroxidaseD NAzymes. [24][25][26] They can also bind to certain fluorogenic molecules, such as protoporphyrin IX (PPIX), to produce as trong fluorescence signal ( Figure 1C). [27][28][29] Therefore, ULX can function as an excellent colorimetric or fluorescent signaling module to build a biosensing system to achieve target detection in 7MU.…”