Microwave has been widely used in many fields,including communication,medical treatment and military industry;however,the corresponding generated radiations have been novel hazardous sources of pollution threating hu...Microwave has been widely used in many fields,including communication,medical treatment and military industry;however,the corresponding generated radiations have been novel hazardous sources of pollution threating human’s daily life.Therefore,designing high-performance microwave absorption materials(MAMs)has become an indispensable requirement.Recently,metal-organic frameworks(MOFs)have been considered as one of the most ideal precursor candidates of MAMs because of their tunable structure,high porosity and large specific surface area.Usually,MOF-derived MAMs exhibit excellent electrical conductivity,good magnetism and sufficient defects and interfaces,providing obvious merits in both impedance matching and microwave loss.In this review,the recent research progresses on MOF-derived MAMs were profoundly reviewed,including the categories of MOFs and MOF composites precursors,design principles,preparation methods and the relationship between mechanisms of microwave absorption and microstructures of MAMs.Finally,the current challenges and prospects for future opportunities of MOF-derived MAMs are also discussed.展开更多
Although stimuli-responsive polymers have appeared as promising materials for drug administration,the effectiveness of these materials on various bioinspired stimuli is still open for dispute.In this work,the stimuli-...Although stimuli-responsive polymers have appeared as promising materials for drug administration,the effectiveness of these materials on various bioinspired stimuli is still open for dispute.In this work,the stimuli-responsive behaviors of radical-containing nonamphiphilic copolymers were investigated using electron paramagnetic resonance(EPR)spectroscopy while altering the pH and reductant concentration.The concentration of radicals in the aqueous solution had a considerable impact on self-assembly.The nitroxide radicals(hydrophobic)were converted to hydroxylamine(hydrophilic)when ascorbic acid(Asc)was added as a reductant,and the assemblies were switched to dissolution with a rate control behavior.The behavior of morphological change was observed in the acidic pH due to the disproportionation reaction of nitroxide radicals forming cationic species.The acquired results give new insights into the colloidal nanoparticles of nonamphiphilic copolymers and encourage the development of comparable responsive nanoparticles with intriguing drug delivery applications.展开更多
The structure of polyolefin has an important influence on its performance and application.Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin.However,research on ...The structure of polyolefin has an important influence on its performance and application.Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin.However,research on the ethylene/1-hexene copolymerization catalyzed by nickel complexes with different steric ligands remains to be refined.Here,three α-dimine nickel catalysts are used to study the ligand effect on catalytic performance in the ethylene/1-hexene copolymerization.Reaction activity,molecular weight,phase-transition temperature and branching density of the resultant copolymer are measured to evaluate the catalytic performance.The results indicate that the steric ligands could exert great effect on the copolymerization.As for the chemical valence of Ni species,detailed EPR demonstrate that the presence of excess xo-catalyst can reduce Ni(Ⅱ)to the lower valence and affect the catalytic performance.展开更多
To overcome the pain and risk of hypoglycemia in insulin administration,glucose-responsive microneedles have been developed by researchers,which could release insulin according to the blood glucose level.We designed a...To overcome the pain and risk of hypoglycemia in insulin administration,glucose-responsive microneedles have been developed by researchers,which could release insulin according to the blood glucose level.We designed a kind of particles by a reversible addition-fragmentation chain transfer(RAFT)method containing a phenylboronic acid group as the sensor of glucose and carrier of insulin.poly(ethylene glycol)(PEG)-2-(dodecylthio(thiocarbonyl)thio)-2-methylpropionic acid(DDMAT)was synthesized as a macromolecular RAFT agent,which was then reacted with 3-acrylamidophenylboronic acid(AAPBA)to synthesize the block copolymer PEG-b-PAAPBA.Glucose-responsive particles loaded with insulin were prepared by self-assembly based on hydrophilic-hydrophobic interactions.Microneedle patches loaded with glucose-responsive particles were prepared using hyaluronic acid as the substrate.The insulin release behavior of the particles in glucose solutions of 0,100,and 400 mg/dL showed significant glucose responsiveness and good biosafety.The results of blood glucose control experiments in rats indicate that a single microneedle patch can effectively maintain normal blood glucose for over 7 h.展开更多
基金Open access funding provided by Shanghai Jiao Tong University.
文摘Microwave has been widely used in many fields,including communication,medical treatment and military industry;however,the corresponding generated radiations have been novel hazardous sources of pollution threating human’s daily life.Therefore,designing high-performance microwave absorption materials(MAMs)has become an indispensable requirement.Recently,metal-organic frameworks(MOFs)have been considered as one of the most ideal precursor candidates of MAMs because of their tunable structure,high porosity and large specific surface area.Usually,MOF-derived MAMs exhibit excellent electrical conductivity,good magnetism and sufficient defects and interfaces,providing obvious merits in both impedance matching and microwave loss.In this review,the recent research progresses on MOF-derived MAMs were profoundly reviewed,including the categories of MOFs and MOF composites precursors,design principles,preparation methods and the relationship between mechanisms of microwave absorption and microstructures of MAMs.Finally,the current challenges and prospects for future opportunities of MOF-derived MAMs are also discussed.
基金the Natural Science Foundation of Zhejiang Province(LHDMZ22H300003)is gratefully acknowledged.
文摘Although stimuli-responsive polymers have appeared as promising materials for drug administration,the effectiveness of these materials on various bioinspired stimuli is still open for dispute.In this work,the stimuli-responsive behaviors of radical-containing nonamphiphilic copolymers were investigated using electron paramagnetic resonance(EPR)spectroscopy while altering the pH and reductant concentration.The concentration of radicals in the aqueous solution had a considerable impact on self-assembly.The nitroxide radicals(hydrophobic)were converted to hydroxylamine(hydrophilic)when ascorbic acid(Asc)was added as a reductant,and the assemblies were switched to dissolution with a rate control behavior.The behavior of morphological change was observed in the acidic pH due to the disproportionation reaction of nitroxide radicals forming cationic species.The acquired results give new insights into the colloidal nanoparticles of nonamphiphilic copolymers and encourage the development of comparable responsive nanoparticles with intriguing drug delivery applications.
基金Financial support from the National Key Research and Development Program(2016YFB0302403)is gratefully acknowledged.
文摘The structure of polyolefin has an important influence on its performance and application.Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin.However,research on the ethylene/1-hexene copolymerization catalyzed by nickel complexes with different steric ligands remains to be refined.Here,three α-dimine nickel catalysts are used to study the ligand effect on catalytic performance in the ethylene/1-hexene copolymerization.Reaction activity,molecular weight,phase-transition temperature and branching density of the resultant copolymer are measured to evaluate the catalytic performance.The results indicate that the steric ligands could exert great effect on the copolymerization.As for the chemical valence of Ni species,detailed EPR demonstrate that the presence of excess xo-catalyst can reduce Ni(Ⅱ)to the lower valence and affect the catalytic performance.
基金supported by the Natural Science Foundation of Zhejiang Province(No.LHDMZ22H300003)the Science and Technology Program of Zhejiang Province(No.2019C03063),China。
文摘To overcome the pain and risk of hypoglycemia in insulin administration,glucose-responsive microneedles have been developed by researchers,which could release insulin according to the blood glucose level.We designed a kind of particles by a reversible addition-fragmentation chain transfer(RAFT)method containing a phenylboronic acid group as the sensor of glucose and carrier of insulin.poly(ethylene glycol)(PEG)-2-(dodecylthio(thiocarbonyl)thio)-2-methylpropionic acid(DDMAT)was synthesized as a macromolecular RAFT agent,which was then reacted with 3-acrylamidophenylboronic acid(AAPBA)to synthesize the block copolymer PEG-b-PAAPBA.Glucose-responsive particles loaded with insulin were prepared by self-assembly based on hydrophilic-hydrophobic interactions.Microneedle patches loaded with glucose-responsive particles were prepared using hyaluronic acid as the substrate.The insulin release behavior of the particles in glucose solutions of 0,100,and 400 mg/dL showed significant glucose responsiveness and good biosafety.The results of blood glucose control experiments in rats indicate that a single microneedle patch can effectively maintain normal blood glucose for over 7 h.
