A novel method was presented to create composite micelles of amphiphilic copolymers and Ag nanoparticles(NPs) in a three-dimensional co-flow focusing microfluidic device(3D CFMD). Self-assembly of the copolymers was i...A novel method was presented to create composite micelles of amphiphilic copolymers and Ag nanoparticles(NPs) in a three-dimensional co-flow focusing microfluidic device(3D CFMD). Self-assembly of the copolymers was initiated by the fast mixing of water and a blend dispersion of hydrophobic Ag NPs and amphiphilic copolymers. At the same time, the hydrophobic Ag NPs enter the core of copolymer micelles, based on the hydrophobic interaction. The copolymer-Ag NPs composite micelles have a core-shell structure with copolymer shell and Ag NPs core. COMSOL Multiphysics is used to simulate the concentration distribution of copolymers and Ag NPs under different flow rates. Co-assembly microfluidic conditions are determined based on simulation results. Under suitable microfluidic conditions, both block copolymers and gradient copolymers can co-assemble with hydrophobic Ag NPs to form composite micelles, respectively. This microfluidic coassembly method will have a good prospect in the preparation of composite micelles of amphiphilic copolymers and metal nanoparticles.展开更多
Microfluidic-NMR spectroscopy has been extended to study the kinetics in supramolecular chemistry and molecular assembly.Kinetics of a multicomponent host-guest supramolecular system containing viologen derivatives, ...Microfluidic-NMR spectroscopy has been extended to study the kinetics in supramolecular chemistry and molecular assembly.Kinetics of a multicomponent host-guest supramolecular system containing viologen derivatives, β-cyclodextrins and cucurbit[7]urils are studied by a PMMA based microfluidic chip combined with a dedicated transmission line probe for NMR detection.By combining microfluidic technology with NMR spectroscopy, the amount of material required for a full kinetic study could be minimized. This is crucial in supramolecular chemistry, which often involves highly sophisticated and synthetically costly building blocks. The small size of the microfluidic structure is crucial in bringing the time scale for kinetic monitoring down to seconds. At the same time, the transmission line NMR probe provides sufficient sensitivity to work at low(2 m M) concentrations.展开更多
In eukaryotic cells,the smallest subunit of chromatin is the nucleosome,which consists of a segment of DNA wound on histone protein cores. Despite many years of effort,the process of nucleosome assembly and disassembl...In eukaryotic cells,the smallest subunit of chromatin is the nucleosome,which consists of a segment of DNA wound on histone protein cores. Despite many years of effort,the process of nucleosome assembly and disassembly is still not very clear. Here,we present a convenient method to investigate the process of nucleosome assembly at the single molecule level. We invented a novel system derived from the yeast nucleoplasmic extracts(YNPE),and demonstrated that the YNPE supports the nucleosome assembly under physiological condition. By combining the total internal reflection fluorescence microscopy with microfluidic flow-cell technique,the dynamic process of nucleosome assembly in YNPE was visualized at single-molecule level. Our system provides a novel in vitro single-molecule tool to investigate the dynamics of nucleosome assembly under physiological conditions.展开更多
Nanowires and nanotubes of diverse material compositions,properties and/or functions have been produced or fabricated through various bottom-up or top-down approaches.These nanowires or nanotubes have also been utiliz...Nanowires and nanotubes of diverse material compositions,properties and/or functions have been produced or fabricated through various bottom-up or top-down approaches.These nanowires or nanotubes have also been utilized as potential building blocks for functional nanodevices.The key for the integration of those nanowire or nanotube based devices is to assemble these one dimensional nanomaterials to specific locations using techniques that are highly controllable and scalable.Ideally such techniques should enable assembly of highly uniform nanowire/nanotube arrays with precise control of density,location,dimension or even material types of nanowires/nanotubes.Numerous assembly techniques are being developed that can quickly align and assemble large quantities of one type or multiple types of nanowires through parallel processes,including flow-assisted alignment,Langmuir-Blodgett assembly,bubble-blown technique,electric/magnetic-field directed assembly,contact/roll printing,knocking-down,etc..With these assembling techniques,applications of nanowire/nanotube based devices such as flexible electronics and sensors have been demonstrated.This paper delivers an overall review of directed nanowire/nanotube assembling approaches and analyzes advantages and limitations of each method.The future research directions have also been discussed.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.51873167 and 50803048)
文摘A novel method was presented to create composite micelles of amphiphilic copolymers and Ag nanoparticles(NPs) in a three-dimensional co-flow focusing microfluidic device(3D CFMD). Self-assembly of the copolymers was initiated by the fast mixing of water and a blend dispersion of hydrophobic Ag NPs and amphiphilic copolymers. At the same time, the hydrophobic Ag NPs enter the core of copolymer micelles, based on the hydrophobic interaction. The copolymer-Ag NPs composite micelles have a core-shell structure with copolymer shell and Ag NPs core. COMSOL Multiphysics is used to simulate the concentration distribution of copolymers and Ag NPs under different flow rates. Co-assembly microfluidic conditions are determined based on simulation results. Under suitable microfluidic conditions, both block copolymers and gradient copolymers can co-assemble with hydrophobic Ag NPs to form composite micelles, respectively. This microfluidic coassembly method will have a good prospect in the preparation of composite micelles of amphiphilic copolymers and metal nanoparticles.
基金supported by the National Basic Research Program of China (2015CB856500)the National Natural Science Foundation of China (21722304, 21573181, 91227111, 91427304)the Fundamental Research Funds for the Central Universities of China (20720160050)
文摘Microfluidic-NMR spectroscopy has been extended to study the kinetics in supramolecular chemistry and molecular assembly.Kinetics of a multicomponent host-guest supramolecular system containing viologen derivatives, β-cyclodextrins and cucurbit[7]urils are studied by a PMMA based microfluidic chip combined with a dedicated transmission line probe for NMR detection.By combining microfluidic technology with NMR spectroscopy, the amount of material required for a full kinetic study could be minimized. This is crucial in supramolecular chemistry, which often involves highly sophisticated and synthetically costly building blocks. The small size of the microfluidic structure is crucial in bringing the time scale for kinetic monitoring down to seconds. At the same time, the transmission line NMR probe provides sufficient sensitivity to work at low(2 m M) concentrations.
基金supported by the National Natural Science Foundation of China (31371264)CAS Interdisciplinary Innovation Team and the Newton Advanced Fellowship (NA140085) from the Royal Society
文摘In eukaryotic cells,the smallest subunit of chromatin is the nucleosome,which consists of a segment of DNA wound on histone protein cores. Despite many years of effort,the process of nucleosome assembly and disassembly is still not very clear. Here,we present a convenient method to investigate the process of nucleosome assembly at the single molecule level. We invented a novel system derived from the yeast nucleoplasmic extracts(YNPE),and demonstrated that the YNPE supports the nucleosome assembly under physiological condition. By combining the total internal reflection fluorescence microscopy with microfluidic flow-cell technique,the dynamic process of nucleosome assembly in YNPE was visualized at single-molecule level. Our system provides a novel in vitro single-molecule tool to investigate the dynamics of nucleosome assembly under physiological conditions.
基金the financial support from Natural Science and Engineering Research Council of Canada (NSERC)funding from Science and Technology Commission of Shanghai Municipality (No.11PJ1403500)+1 种基金the Open Project Program of State Key Laboratory of Industrial Control Technology (No.ICT1113)Innovation Program of Shanghai Municipal Education Commission (No.12YZ022)
文摘Nanowires and nanotubes of diverse material compositions,properties and/or functions have been produced or fabricated through various bottom-up or top-down approaches.These nanowires or nanotubes have also been utilized as potential building blocks for functional nanodevices.The key for the integration of those nanowire or nanotube based devices is to assemble these one dimensional nanomaterials to specific locations using techniques that are highly controllable and scalable.Ideally such techniques should enable assembly of highly uniform nanowire/nanotube arrays with precise control of density,location,dimension or even material types of nanowires/nanotubes.Numerous assembly techniques are being developed that can quickly align and assemble large quantities of one type or multiple types of nanowires through parallel processes,including flow-assisted alignment,Langmuir-Blodgett assembly,bubble-blown technique,electric/magnetic-field directed assembly,contact/roll printing,knocking-down,etc..With these assembling techniques,applications of nanowire/nanotube based devices such as flexible electronics and sensors have been demonstrated.This paper delivers an overall review of directed nanowire/nanotube assembling approaches and analyzes advantages and limitations of each method.The future research directions have also been discussed.
