Proximity-Enhanced Electrochemiluminescence Sensing Platform for Effective Capturing of Exosomes and Probing Internal MicroRNAs Involved in Cancer Cell Apoptosis

Evaluating early apoptosis-related cellular MiRNAs with an ultrasensitive electrochemiluminescence nanoplatform

“…Based on the above results, we further detected the concentrations of endogenous miR-21 and miR-133a in the cells. It was reported that miR-21 was highly expressed in both MCF-7 cells and A549 cells, 14,30–32 and early apoptosis could be induced by treating the two cell lines with 100 nM DOX for 4 h. 21 Therefore, we detected the concentrations of miR-21 and miR-133a in the two cell lines before and after drug treatment, analyzed the differences, and selected the cell line with more obvious miRNA level changes after drug treatment for further study, as shown in Fig. 5A and B.…”

“…For example, electrochemiluminescence (ECL) detection has proved to be a powerful tool for the detection of miRNAs without nucleic acid amplification. 21–23…”

Improved Catalytic Activity of Spherical Nucleic Acid Enzymes by Hybridization Chain Reaction and Its Application for Sensitive Analysis of Aflatoxin B1

“…Spherical nucleic acids enzymes (SNAzymes) are usually fabricated using functional DNA strands decorated on gold nanoparticles (AuNPs), which are extensively applied in biosensing depending on their ease of synthesis, programmable functionalization, and high stability [1][2][3][4][5]. Compared to other DNA sequences, G-quadruplex (G4) exhibits higher density of the nucleic acid layer after it is modified on the surface of AuNPs through the Au-S covalent band [6], showing good peroxidase-mimicking activity with the presence of the cofactor hemin [7][8][9][10]. However, G4 was formed via the Hoogsteen base pair instead of the traditional Watson-Crick base pair, which occupied more spaces on the limited surface of gold core [11][12][13], resulting in poor catalytic capacity due to the decreased local catalytic substrate concentrations [14][15][16].…”

Stimulus-Responsive Four-Stranded DNA Nanoring Assembly to Host Multiple Nanosilver Clusters for Cooperatively Enhanced Fluorescence Biosensing

“…By using DNA as a building block, a variety of exquisite well-defined framework nucleic acids (FNAs) with varied size and shape have been actively constructed via “bottom-up” or “top-down” self-assembly strategies. − Basically, once the growth begins, reactive DNA species spontaneously bind to each other during thermal annealing, as by default all of them are activated. , With the increasing progress in DNA nanotechnology, such structurally ordered FNAs as tetrahedra, tiles, nanopores, and origami possess high yield, precise addressability, easy modification, rigidity, and good biocompatibility . These performances mean FNAs hold great promise for extensive applications in molecular recognition, biosensing, cell imaging, drug delivery, and precision diagnosis. ,− In particular, the spatial addressability sheds light on the FNA nanostructures as precise matrixes to site-specifically anchor customized elements or biomolecules for signal transduction, because the nicks, stretching toeholds, or side arms in the scaffolds provide huge flexibilities, diversities, and accessibilities. ,, This is very useful to bind the targeted analytes of interest recognizably, which is readily translated in different signal settings. For example, one capture sequence tethered in a tetrahedral FNA effectively immobilized the trigger to initiate a hybridization chain reaction for signal amplification, on which a highly sensitive electrochemical platform was devised .…”