Biodegradable multilayer films of alternating poly- L -lysine(PLL) and deoxyribonucleic acid(DNA) layers were fabricated onto quartz substrates by the layer-by-layer(LbL) self-assembly method. UV-Visible spectra showe...Biodegradable multilayer films of alternating poly- L -lysine(PLL) and deoxyribonucleic acid(DNA) layers were fabricated onto quartz substrates by the layer-by-layer(LbL) self-assembly method. UV-Visible spectra showed that PLL and DNA can successfully be adsorbed and form multilayer films via LbL. Degradation experiments were carried out with enzymes. AFM was utilized to measure the changes of thickness of multilayer films. The gradual decrease of thickness of multilayer films with the increase of degradation time was observed. In our experiments, about 85% of films was degraded in 35 h. Our study provided a novel gene delivery system using LbL method,which may be applied to gene therapy.展开更多
Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can ...Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly（allylamine hydrochloride） （PAH） was used as polycation and sodium dodecyl sulphate （SDS） was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-bylayber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex fihns is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.展开更多
A new biomimetic material for artificial blood vessel with in situ catalytic generation of nitric oxide(NO) was prepared in this study. Organoselenium immobilized polyethyleneimine as NO donor catalyst and sodium algi...A new biomimetic material for artificial blood vessel with in situ catalytic generation of nitric oxide(NO) was prepared in this study. Organoselenium immobilized polyethyleneimine as NO donor catalyst and sodium alginate were alternately loaded onto the surface of electrospun polycaprolactone matrix via electrostatic layer-by-layer self-assembly. This material revealed significant NO generation when contacting NO donor S-nitrosoglutathione(GSNO). Adhesion and spreading of smooth muscle cells were inhibited on this material in the presence of GSNO, while proliferation of endothelial cells was promoted. In vitro platelet adhesion and arteriovenous shunt experiments demonstrated good antithrombotic properties of this material, with inhibited platelet activation and aggregation, and prevention of acute thrombosis. This study may provide a new method of improving cellular function and antithrombotic property of vascular grafts.展开更多
Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low...Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low roughness and high homogeneity.Various innovative approaches have been developed for MOF thin film fabrication.Among these advanced materials,surface-attached metal-organic frameworks(SURMOFs) are an important class of MOF films.SURMOFs,fabricated in a step-by-step liquid phase epitaxial(LPE) fashion by alternating deposition of metal and organic linker precursors on a functionalized substrate,for example,thiolate-based self-assembled monolayers(SAMs),have already exhibited their utility in both research and potential applications.SURMOFs combine surface science and the chemistry of MOFs,possessing the following unique advantages that cannot be accessed through other methods:(i) precisely controlling thickness,roughness and homogeneity as well as growth orientation,(ii) studying of MOF growth mechanism,(iii) modifying/tailoring MOFs' structures during the SURMOF growth and thus creating customizable properties,and(iv) existing in the form of thin film/membrane for direct applications,for example,as sensors.This review discusses the oriented and crystalline SURMOFs fabricated by LPE approach,covering their preparation,growth mechanism,and characterization methodology as well as applications based upon the most newly updated knowledge.展开更多
文摘Biodegradable multilayer films of alternating poly- L -lysine(PLL) and deoxyribonucleic acid(DNA) layers were fabricated onto quartz substrates by the layer-by-layer(LbL) self-assembly method. UV-Visible spectra showed that PLL and DNA can successfully be adsorbed and form multilayer films via LbL. Degradation experiments were carried out with enzymes. AFM was utilized to measure the changes of thickness of multilayer films. The gradual decrease of thickness of multilayer films with the increase of degradation time was observed. In our experiments, about 85% of films was degraded in 35 h. Our study provided a novel gene delivery system using LbL method,which may be applied to gene therapy.
文摘Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly（allylamine hydrochloride） （PAH） was used as polycation and sodium dodecyl sulphate （SDS） was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-bylayber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex fihns is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.
基金supported by the National Basic Research Program of China(2012CB725204)National Natural Science Foundation of China(51073081,31170030 and J1103503)+1 种基金Program for Changjiang Scholars and Innovative Research Team in University(IRT13023)the Natural Science Foundation of Tianjin,China(13JCYBJC24900 and 13JCZDJC-27800)
文摘A new biomimetic material for artificial blood vessel with in situ catalytic generation of nitric oxide(NO) was prepared in this study. Organoselenium immobilized polyethyleneimine as NO donor catalyst and sodium alginate were alternately loaded onto the surface of electrospun polycaprolactone matrix via electrostatic layer-by-layer self-assembly. This material revealed significant NO generation when contacting NO donor S-nitrosoglutathione(GSNO). Adhesion and spreading of smooth muscle cells were inhibited on this material in the presence of GSNO, while proliferation of endothelial cells was promoted. In vitro platelet adhesion and arteriovenous shunt experiments demonstrated good antithrombotic properties of this material, with inhibited platelet activation and aggregation, and prevention of acute thrombosis. This study may provide a new method of improving cellular function and antithrombotic property of vascular grafts.
基金the European Union for funding the research projects on MOF thin films (Priority Program 1362 of the DFG)SUR-MOFs(6th FP, NMP4-CT-2006-032109)
文摘Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low roughness and high homogeneity.Various innovative approaches have been developed for MOF thin film fabrication.Among these advanced materials,surface-attached metal-organic frameworks(SURMOFs) are an important class of MOF films.SURMOFs,fabricated in a step-by-step liquid phase epitaxial(LPE) fashion by alternating deposition of metal and organic linker precursors on a functionalized substrate,for example,thiolate-based self-assembled monolayers(SAMs),have already exhibited their utility in both research and potential applications.SURMOFs combine surface science and the chemistry of MOFs,possessing the following unique advantages that cannot be accessed through other methods:(i) precisely controlling thickness,roughness and homogeneity as well as growth orientation,(ii) studying of MOF growth mechanism,(iii) modifying/tailoring MOFs' structures during the SURMOF growth and thus creating customizable properties,and(iv) existing in the form of thin film/membrane for direct applications,for example,as sensors.This review discusses the oriented and crystalline SURMOFs fabricated by LPE approach,covering their preparation,growth mechanism,and characterization methodology as well as applications based upon the most newly updated knowledge.
