https://www.selleckchem.com/products/epz-5676.html The limit of detection (LOD) was 229 particles μL-1 with a linear range from 5 × 102 particles μL-1 to 5 × 105 particles μL-1. An electrochemical biosensor can detect exosomes secreted by various cancer cells such as HeLa, OVCAR and BT474, and shows a high specificity even in serum samples, thus demonstrating its great potential in the application of clinical diagnostics. This proposed electrochemical biosensor provides a facile and efficient tool for the early diagnosis of cancers.MicroRNAs (miRNAs) are related to many biological processes and regarded as biomarkers of disease. Rapid, sensitive, and specific methods for miRNA assay are very important for early disease diagnostic and therapy. In the present work, an ultrasensitive electrochemical biosensing platform has been developed for miRNA-21 assay by combining CRISPR-Cas13a system and catalytic hairpin assembly (CHA). In the presence of miRNA-21, it would hybridize with the spacer region of Cas13a/crRNA duplex to activate the cleavage activity of CRISPR-Cas13a system, leading to the release of initiator of CHA to generate amplified electrochemical signals. Base on the CRISPR-Cas13a-mediated cascade signal amplification strategy, the developed electrochemical biosensing platform exhibited high sensitivity with a low detection limit of 2.6 fM (S/N = 3), indicating that the platform has great potential for application in early clinical diagnostic.Cerium is the most abundant rare earth element (REE) in the solar photosphere, CI chondrites, and the Earth. It has four main stable isotopes (masses 136,138,140, and 142), with 138Ce being the most studied species, used in geochronology and petrogenesis. In addition, more abundant 140Ce and 142Ce are suggested to be potentially applicable in geochemical investigations. In this work, we developed a modified four-step ion chromatography procedure for Ce chemical separation. Using a MC-ICPMS, we designed a cup configuratio