Framework and Spherical Nucleic Acids Synergistically Enhanced Electrochemiluminescence Nanosensors for Rapidly Diagnosing Acute Myocardial Infarction Based on Circulating MicroRNA Levels

Abstract

Acute myocardial infarction (AMI)-related micro-RNAs (miRNAs) in circulating blood have been proved as promising biomarkers for AMI diagnosis. The detection of these miRNAs at ultralow levels usually requires nucleic acid amplification strategies to improve the sensitivity at the cost of time. Given that the first hour after an AMI attack is the golden time for saving AMI patients' lives, shortening the time of ultrasensitive miRNA analysis is of great significance for clinical AMI diagnosis. Toward this goal, here we present a direct electrochemiluminescence (ECL) sensing strategy for fast and ultrasensitive miRNA detection, circumventing the time-consuming signal amplification steps. Target miRNAs are directly hybridized with two probe strands that are attached to a covalently hemin-modified spherical nucleic acid enzyme (SNAzyme) and a truncated triangular pyramid DNA nanoplatform on the electrode, respectively. Both of them improve the ECL signal and meanwhile reduce the background, thereby remarkably promoting the detection sensitivity of target miRNAs. It enables the rapid detection of an AMI-related miRNA (miR-499) at 10 aM in human serum within 30 min using the SNAzyme-catalyzed luminol-H 2 O 2 ECL reaction. This sensing strategy is then utilized for AMI diagnosis via probing endogenous miR-499 in patients' circulating blood with endogenous miR-16 as an intrinsic reference, showing a significant difference (P < 0.001) between the miR-499 levels of patients and the healthy.

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

“…23,24 So we envisage that tethering this aptamer to one of the TTP structures will allow exosomes to be immobilized there for proximity, releasing internal miRNAs that are involved in the ECL reaction on the TTP nanoplatform. 22 Such a proximity effect in principle contributes to the ECL readout, as reported previously. 6,25,26 With this idea in mind, herein we build two TTP structures functionalized with the CD63-binding aptamer 27 and probe strand, respectively, and then conjugate them on one edge to form a dimeric analytical platform (Figure 1), reported with the luminol-H 2 O 2 ECL system catalyzed by covalently heminmodified spherical nucleic acid enzymes (c-SNAzymes).…”

“…Based on it, here, we seek to build a dimeric TTP-based analytical platform that integrates exosome capturing and proximity miRNA sensing. It has been demonstrated that exosomes can be captured by a DNA aptamer that specifically binds CD63 proteins on the surface. , So we envisage that tethering this aptamer to one of the TTP structures will allow exosomes to be immobilized there for proximity, releasing internal miRNAs that are involved in the ECL reaction on the TTP nanoplatform . Such a proximity effect in principle contributes to the ECL readout, as reported previously. ,, …”

“…6,25,26 With this idea in mind, herein we build two TTP structures functionalized with the CD63-binding aptamer 27 and probe strand, respectively, and then conjugate them on one edge to form a dimeric analytical platform (Figure 1), reported with the luminol-H 2 O 2 ECL system catalyzed by covalently heminmodified spherical nucleic acid enzymes (c-SNAzymes). 22 Exosome capturing and the immediate probing of internal miRNAs are carried out on these two adjacent TTP structures; thereby, the sensitivity for exosomal miRNA detection is apparently promoted via local diffusion limitation. 28,29 ■ EXPERIMENTAL SECTION Materials and Reagents.…”

“…FNA-based sensing interfaces provide a universal platform for analyzing various biomarkers, including miRNAs, DNAs, proteins, exosomes, and cells. ,− Among them, a truncated triangular pyramid (TTP)-based ECL sensing platform was developed in our previous work for ultrasensitive miRNA detection without signal amplification. Based on it, here, we seek to build a dimeric TTP-based analytical platform that integrates exosome capturing and proximity miRNA sensing.…”

Silver Nanocluster-Tagged Electrochemiluminescence Immunoassay with a Sole and Narrow Triggering Potential Window

“…Electrochemiluminescence (ECL), a powerful optical technology of low background noise, wide dynamic range, and high sensitivity, − is being widely used for immunoassays , and DNA probe analyses. , An ECL assay is conducted in either a total-photon-collected − or a wavelength-resolved way. − The wavelength-resolved ECL is normally conducted with area array detectors, , such as charge-coupled devices , and complementary metal-oxide semiconductors. , Although the dispersion of ECL can enable multiple immunoassays without spectral cross-talk, , the ECL photons at a given wavelength are much less than the total ECL photons. From this point, the commercialized ECL immunoassay is normally conducted in a total-photon-collected way with a photomultiplier tube as a detector. , …”