Multiarmed DNA jumper and metal-organic frameworks-functionalized paper-based bioplatform for small extracellular vesicle-derived miRNAs assay.

Small extracellular vesicle-derived microRNAs (sEV-miRNAs) have emerged as promising noninvasive biomarkers for early cancer diagnosis. Herein, we developed a molecular probe based on three-dimensional (3D) multiarmed DNA tetrahedral jumpers (mDNA-Js)-assisted DNAzyme activated by Na+, combined with a disposable paper-based electrode modified with a Zr-MOF-rGO-Au NP nanocomplex (ZrGA) to fabricate a novel biosensor for sEV-miRNAs Assay. Zr-MOF tightly wrapped by rGO was prepared via a one-step method, and it effectively aids electron transfer and maximizes the effective reaction area. In addition, the mechanically rigid, and nanoscale-addressable mDNA-Js assembled from the bottom up ensure the distance and orientation between fixed biological probes as well as avoid probe entanglement, considerably improving the efficiency of molecular hybridization. The fabricated bioplatform achieved the sensitive detection of sEV-miR-21 with a detection limit of 34.6 aM and a dynamic range from100 aM to 0.2 µM. In clinical blood sample tests, the proposed bioplatform showed results highly consistent with those of qRT-PCRs and the signal increased proportionally with the NSCLC staging. The proposed biosensor with a portable wireless USB-type analyzer is promising for the fast, easy, low-cost, and highly sensitive detection of various nucleic acids and their mutation derivatives, making it ideal for POC biosensing.

Modularized Enzymatic Tandem Reaction for tsRNA Detection.

tRNA-derived small RNA (tsRNA) has emerged as a new biomarker for early diagnosis and prognosis prediction of breast cancer. Like the detection of other small non-coding RNAs, the traditional DNA circuit could be used for the tsRNA detection. However, the highly coupling DNA strands in the circuit increase the difficulty of design and could raise a false-positive signal. Here, we demonstrated a versatile modularized enzymatic tandem reaction, namely, reverse-transcribed nicking exponential truncation (RT-NExT). This enzymatic reaction was constructed by cohesive modules, which can work independently or in assembly. Each module could amplify and initiate the downstream module. The RT-NExT reaction could detect 10-18 M ts-66 or ts-86 within 10 min and exhibited excellent consistency to the qRT-PCR when measuring the tsRNA expression level of breast cancer or healthy patients. RT-NExT provides an appealing detection strategy for further research on the clinical diagnosis with tsRNAs.