ABSTRACT
An array of novel 7-methoxyl-2,3-disubstituted quinoxaline derivatives was designed, synthesized and their potential antihypertensive activities were examined, in an attempt to discover potent small molecules with vasorelaxant effects. The vasoactivities of these compounds on vascular tone, as well as underlying mechanisms were hereby explored. Results showed that five compounds (7s, 7t, 7v, 7w, 7γ) could induce endothelium-independent relaxation in high extracellular K+- and phenylephrine-precontracted C57 mice aortic rings. These five compounds, unlike other commonly used vasodilators, could slowly but effectively inhibit vasoconstriction.
Subject(s)
Antihypertensive Agents/pharmacology , Aorta, Thoracic/drug effects , Endothelium, Vascular/drug effects , Quinoxalines/pharmacology , Vasodilator Agents/pharmacology , Animals , Antihypertensive Agents/chemical synthesis , Antihypertensive Agents/chemistry , Aorta, Thoracic/metabolism , Dose-Response Relationship, Drug , Endothelium, Vascular/metabolism , Male , Mice , Mice, Inbred C57BL , Molecular Structure , Phenylephrine , Quinoxalines/chemical synthesis , Quinoxalines/chemistry , Structure-Activity Relationship , Vasodilator Agents/chemical synthesis , Vasodilator Agents/chemistryABSTRACT
Reversing the switching of DNA scissors with precisely control remains a compelling goal. Herein, based on strand displacement reaction within single step, the DNA scissor realized reversible switching and further controlled the distance of end strands along the movement of DNA scissor, which has been applied for the development of a regenerated sensing platform for the ultrasensitive detection of microRNA-21 (miRNA-21) with the electrochemiluminescence (ECL) complex (PEI-Ru(II)) as luminophores and diethylenetriamine (DETA) as the coreactant. In the presence of ferrocene-labeled DNA (Fc-DNA), the DETA-labeled DNA scissor clockwise switched to "off" state based on strand displacement reaction, resulting in the significant ECL quenching of Ru(II) system. Next, by using miRNA-21 as the motive fuel, the configuration of DNA scissor could be anticlockwise switched, which significantly enhanced the ECL intensity of Ru(II) complex due to the releasing of Fc-DNA and the proximity between DETA and Ru(II) complex. The reversible switching of DNA scissor led to the remarkably enhancing of ECL signal, realizing ultrasensitive detection of miRNA-21 with an excellent detection limit of 0.17 fM, which was also applied in miRNA detection successfully from different cancer cells. Impressively, the reversible switching of DNA scissor biosensor was able to realize the regeneration of the biosensing platform by adding an additional single stranded DNA (ssDNA) based on strand displacement reaction within a single step, providing a novel concept for constructing simple and sensitive regenerated biosensor.
Subject(s)
Biosensing Techniques/methods , MicroRNAs/analysis , Cell Line, Tumor , Coordination Complexes/chemistry , DNA, Single-Stranded/chemistry , DNA, Single-Stranded/metabolism , Electrochemical Techniques , Ferrous Compounds/chemistry , Humans , Limit of Detection , Luminescent Measurements , Metallocenes/chemistry , MicroRNAs/chemistry , MicroRNAs/metabolism , Polyamines/chemistry , Ruthenium/chemistryABSTRACT
Herein, a dual microRNA (miRNA) powered bi-directional DNA walking machine with precise control was developed to fabricate an enzyme-free biosensor on the basis of distance-based electrochemiluminescence (ECL) energy transfer for multiple detection of miRNAs. By using miRNA-21 as the driving force, the DNA walker could move forth along the track and generated quenching of ECL response due to the proximity between Au nanoparticles (AuNPs) and Mn2+ doped CdS nanocrystals (CdS:Mn NCs) film as the ECL emitters, realizing ultrasensitive determination of miRNA-21. Impressively, once miRNA-155 was introduced as the driving force, the walker could move back along the track automatically, and surface plasmon resonance (SPR) occurred owing to the appropriate large separation between AuNPs and CdS:Mn NCs, achieving an ECL enhancement and realizing ultrasensitive detection of miRNA-155. The bi-directional movement of the DNA walker on the track led to continuous distance-based energy transfer from CdS:Mn NCs film by AuNPs, which resulted in significant ECL signal variation of CdS:Mn NCs for multiple detection of miRNA-21 and miRNA-155 down to 1.51 fM and 1.67 fM, respectively. Amazingly, the elaborated biosensor provided a new chance for constructing controllable molecular nanomachines in biosensing, disease diagnosis, and clinical analysis.
