摘要：Here, we report a study of ion transport across graphene oxide （GO） membranes of various thicknesses, made by vacuum filtration of GO aqueous solutions. The diffusive transport rates of two charge-equivalent ruthenium complex ions Ru（bpy）3^2＋ and Ru（phen）32% with a sub-angstrom size difference, are distinguishable through GO membranes and their ratio can be a unique tool for probing the transport-relevant pore structures. Pore and slit-dominant hindered diffusion models are presented and correlated to experimental results. Our analysis suggests that ion transport is mostly facilitated by large pores （larger than 1.75 nm in diameter） in the relatively thin GO membranes, while slits formed by GO stacking （less than 1.42 nm in width） become dominant only in thick membranes. By grafting PEG molecules to the lateral plane of GO sheets, membranes with enlarged interlayer spacing were engineered, which showed drastically increased ion transport rates and lower distinction among the two ruthenium complex ions, consistent with the prediction by the slit-dominant steric hindered diffusion model.

摘要：MicroRNAs(miRNAs)are a class of endogenous short noncoding *** regulate gene expression and function,essential to biological *** is necessary to develop an efficient detection method to determine these valuable biomarkers for the diagnosis of *** this paper,we proposed a general and rapid method for sensitive and quantitative detection of miRNA by combining CRISPR–Cas12a and rolling circle amplification(RCA)with the precircularized ***,the detection of miRNA-21 could be completed in 70 min with a limit of detection of 8.1 pM with high *** reaction time was reduced by almost 4 h from more than 5 h to 70 min,which makes detection more *** design improves the efficiency of CRISPR–Cas and RCA-based sensing strategy and shows great potential in lab-based detection and point-of-care test.