Ratiometric Fluorescence Detection of Colorectal Cancer-Associated Exosomal miR-92a-3p with DSN-Assisted Signal Amplification by a MWCNTs@Au NCs Nanoplatform

Abstract

The detection of miRNA shows great promise in disease diagnosis. In this work, a ratiometric fluorescent biosensor based on multi-walled carbon nanotubes@gold nanoclusters (MWCNTs@Au NCs) and duplex-specific nuclease (DSN)-assisted signal amplification was fabricated for miRNA detection. Colorectal cancer (CRC)-associated miR-92a-3p extracted from exosomes was selected as the target. MWCNTs@Au NCs performs the dual functions of fluorescence quencher and internal fluorescence reference. In the absence of miR-92a-3p, an Atto-425-modified single-stranded DNA probe is adsorbed on MWCNTs@Au NCs, resulting in the quenching of Atto-425. In the presence of miR-92a-3p, the duplex is formed by hybridization of the probe and miR-92a-3p and leaves the MWCNTs@Au NCs, resulting in the fluorescence recovery of Atto-425. DSN can cleave the probe and result in the release of miR-92a-3p. The released miR-92a-3p can hybridize with other probes to form a signal amplification cycle. The fluorescence of MWCNTs@Au NCs remains stable and constitutes a ratiometric fluorescence system with that of Atto-425. A detection concentration interval of 0.1–10 pM and a limit of detection of 31 fM was obtained under optimized measurement conditions. In addition, the accuracy of the biosensor was validated by detecting the concentration of miR-92a-3p extracted from clinical exosome samples.

Signal-On Fluorescence Biosensor for Detection of miRNA-21 Based on ROX labeled Specific Stem-Loop Probe

“…The Measurements of various fluorescence emission spectra indicated that 12 minutes is the optimal duration for duplex formation (Figure 4C). MWCNTs@Au NCs, Atto-425 miR-92a-3p 0.1 -10 0.031 (43) In this study miRNA-21 -1.12 relationship between fluorescence intensity and cDNA concentration was nonlinear, described by the equation y = -1.2031x + 11.986 with an R 2 value of 0.7594. By examining the fluorescence response of the biosensor to cDNA and a mismatched DNA, a qualitative analysis was conducted to assess the selectivity of the miRNA sensing platform.…”

Emerging Sensing and In Situ Detection Technologies for the Analysis of Extracellular Vesicle miRNAs

“…EV‐miRNAs are associated with the progression of many cancers, and several emerging assays have been validated in clinical samples, mostly from serum or plasma, but also from urine and some tissue fluids. These assays detect single or multiple miRNAs for the diagnosis of related diseases such as PDAC, [ 98 ] breast cancer, [ 99 ] CRC, [ 100 ] thyroid cancer, [ 101 ] and oral squamous cell carcinoma. [ 102 ] Emerging assays have shown good performance in the detection of EV‐miRNAs due to their high specificity and sensitivity ( Table 2 ).…”

Visualization of Polymer–Surfactant Interaction by Dual-Emissive Gold Nanocluster Labeling

“…For example, Yang et al achieved the imaging of the CAC and PSP points of the sodium carboxymethyl cellulose-stepanol WA-100 system [ 18 ]. Among these techniques, the fluorimetry-based ones have attracted wide interest because of their high sensitivity and low background [ 19 , 20 ]. For instance, Jiao et al reported a fluorescence imaging tool that illustrates the CAC and PSP points of chitosan and tetraphenylethene-modified sodium dodecyl sulfonate surfactant (TPE-SDS) [ 21 ].…”