G-triplex: A new type of CRISPR-Cas12a reporter enabling highly sensitive nucleic acid detection

Microfluidic space coding for multiplexed nucleic acid detection via CRISPR-Cas12a and recombinase polymerase amplification

“…The sample is loaded into the hub well at the center, and the spoke microchannels homogeneously distribute the sample into 30 labeled wells pre-loaded with a specific Cas12a-detection mix containing Cas12a, crRNA, and a fluorescence reporter. The reporter used is a fluorophore quencher (FQ)-labeled oligonucleotide named TBA11 (GGTTGGTGTGG), a truncated form of thrombin binding aptamer (TBA), that has been proven to have higher sensitivity than a normal ssDNA reporter 31 , 32 . If the HPV DNA matches the crRNA, the relevant wells (three wells used as a group for testing the same HPV subtype) will show a bright fluorescence signal.…”

Telomere G-triplex lights up Thioflavin T for RNA detection: new wine in an old bottle

“…1a ), the FRET signal was very low (~ 0.25). However, the FRET efficiency significantly increased to 0.59 and 0.64 in the solution with Na + and K + , respectively [ 16 , 24 , 25 ]. This result revealed that the ht-G3 sequence formed a higher-order structure that resulted in the approaching of the two fluorescent probes.…”

“…However, the too-stable G4 structures could bring some problems in cases requiring the rearrangement of the high-order structure during target DNA or RNA binding [ 11 – 13 ]. Therefore, many researchers have endeavored to find out sequences forming G-triplexes (G3s) that have three-stranded noncanonical secondary structure and similar biochemical functions like G4s but relatively less stability than G4s [ 12 , 14 – 16 ]. For example, a truncated form of the G4 sequence thrombin binding aptamer (TBA), TBA11 (11-nt sequence, 5′-GGTTGGTGTGG-3′), was obtained and found to be able to fold into a G3 structure [ 14 , 15 , 17 ].…”

A DNA–Cu nanocluster and exonuclease I integrated label-free reporting system for CRISPR/Cas12a-based SARS-CoV-2 detection with minimized background signals

“…34,35 Based on this status quo, the reporter innovation has sprung up, which provided few alternative reporter forms, such as nanomaterial-medicated reporters, 36,37 double-stranded reporters, 38 and G-quadruplex reporters. 39,40 For example, gold nanoparticle-functionalized reporters have been developed; however, costly labels and harsh synthetic conditions have limited their applications. 41 Certain label-free reporters, such as Gquadruplexes, have been developed, while their strict requirement for buffer conditions reduced their feasibility and universality in CRISPR-driven biosensing.…”