A one-pot isothermal Fluorogenic Mango II arrays-based assay for label-free detection of miRNA.

The capability to detect a small number of miRNAs in clinical samples with simplicity, selectivity, and sensitivity is immensely valuable, yet it remains a daunting task. Here, we described a novel Mango II aptamers-based sensor for the one-pot, sensitive and specific detection of miRNAs. Target miRNA-initiated mediated catalyzed hairpin assembly (CHA) would allow for the production of plenty of DNA duplexes and the formation of the complete T7 promoter, motivating the rolling circle transcription (RCT). Then, the subsequent RCT process efficiently generates a huge number of repeating RNA Mango II aptamers, brightened by the incorporation of fluorescent dye TO1-B for miRNA quantification, realizing label-free and high signal-to-background ratio. Moreover, this assay possesses a remarkable ability to confer high selectivity, enabling the distinction of miRNAs among family members with mere 1- or 2- nucleotide (nt) differences. By employing the proposed assay, we have successfully achieved a sensitive evaluation of miR-21 content in diverse cell lines and clinical serum samples. This offers a versatile approach for the sensitive assay of miRNA biomarkers in molecular diagnosis.

Sensitive Detection of Escherichia coli O157:H7 Using Allosteric Probe and Hairpin Switches-Based Isothermal Transcription Amplification.

Pathogens pose a serious threat to public and population health, leading to serious outbreak and spread of diseases irrespective of the region. The capability to directly, sensitively, and specifically detect viable pathogens in low numbers in food and clinical samples is very desirable but remains a challenge. In this work, we present a novel assay of a combination of an aptamer-based allosteric probe and hairpin switch-controlled T7 RNA polymerase-based isothermal transcription amplification, which enables rapid, ultrasensitive, label-free detection of direct pathogens. It can detect Escherichia coli as low as 73.2 CFU/mL. Moreover, with the usage of the proposed assay, sensitive quantification of E. coliO157:H7 in milk samples has been achieved, showing significant potential as a simple and sensitive tool to quantify pathogens in milk and other foods.

Hairpin Switches-Based Isothermal Transcription Amplification for Simple, Sensitivity Detection of MicroRNA.

The ability to simply, selectively, and sensitively detect low numbers of miRNAs in clinical samples is highly valuable but remains a challenge. In this work, we present a novel miRNA detection system by using the elaborately designed hairpin switch, where the T7 primer, template, target recognize sequence, and light-up RNA aptamer template are edited and embedded in one single-stranded DNA hairpin structure. In the beginning, the hairpin switch maintained the hairpin structure 1, in which the ds promoter of T7 polymerase was disrupted, thus the transcription reaction of T7 polymerase was inhibited. After binding to the target, the hairpin switch 1 was unfolded and turned to the hairpin structure 2. This switch initiates the in vitro T7 transcription reaction, producing plenty of RNA transcripts containing RNA aptamers. Consequently, transcribed tremendous RNA aptamers lighted up the fluorophore for quantitative analysis. Compared with the existing T7 polymerase-based amplification system, this strategy exhibits several advantages, including simplicity, convenience, and high selectivity and sensitivity. The experimental results demonstrated that we could achieve the quantification of miRNA in buffer and complex biological samples.

Engineering a novel microcapsule of Cu9S5 core and SnS2 quantum dot/carbon nanotube shell as a Li-ion battery anode.

A novel microcapsule composed of Cu9S5 and SnS2 quantum dots (QDs)/carbon nanotubes (CNTs) prepared through a microfluidic approach was developed for a Li-ion battery anode. CNTs enhance the conductivity, while pores in the shell facilitate electrolyte penetration, and void in the microcapsule buffers the volume change. The microcapsule-based anode displayed stable capacity, a Coulombic efficiency of 99.9%, and reversible rate-performance at temperatures of -10 °C and 45 °C, which are significant for developing high-performance energy-storage materials and battery systems.