We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mech...We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.展开更多
Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bendi...Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.展开更多
Two derivatives of tetraphenylethene (TPE) were synthesized through one step cross McMurry coupling reaction. Both luminogens exhibit aggregation-induced emission (AIE) and crystallization induced emission enhancement...Two derivatives of tetraphenylethene (TPE) were synthesized through one step cross McMurry coupling reaction. Both luminogens exhibit aggregation-induced emission (AIE) and crystallization induced emission enhancement (CIEE). The emissions of both luminogens could be switched between blue and green through reversible modulation of morphology with thermal, organic solvent fuming and mechanical stimuli. Thus we provide a possible design strategy for emission switching materials.展开更多
In an effort to develop biomaterials to meet guided tissue regeneration （GTR） standards for periodontal tissue recovery, a homogeneous and transparent chitosan （CS）/hydroxyapatite （HA） membrane with potential ap...In an effort to develop biomaterials to meet guided tissue regeneration （GTR） standards for periodontal tissue recovery, a homogeneous and transparent chitosan （CS）/hydroxyapatite （HA） membrane with potential applications as GTR barrier in periodontal therapy has been prepared via in situ compositing. The membrane has been designed to have a smoothrough asymmetric structure that meets the demand for GTR. Component and morphology of the membrane are characterized by XRD and SEM. It can be indicated that HA was in situ synthesized uniformly in the CS membrane. Mechanical experiments of the membranes with various HA contents show that their tensile strengths are adequate for periodontal therapy. Biological properties of the membrane have been performed by cell toxicity assays, hemolysis tests and animal experiments. Results indicate that the membrane has good biocompatibility and inductive effect for cell growth. Therefore this membrane can be potentially applied as GTR barrier membrane for periodontal tissue regeneration.展开更多
We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precu...We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA （P2） was derived by desilylation of the pristine PA with trimethylethynylsilane side chains （P1）. P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane （M） under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps （from P1 to P3 via precursor P2） and one-pot （from P1 to P3 without separation and purification of P2） were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.展开更多
Fluorescent probes play a key role in modern biomedical research. As compared to inorganic quantum dots (QDs) composed with heavy metal elements, organic dye-based fluorescent nanoparticles have higher biocompatibilit...Fluorescent probes play a key role in modern biomedical research. As compared to inorganic quantum dots (QDs) composed with heavy metal elements, organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety. However, traditional organic fluorophores tend to quench fluorescence upon aggregation, which is known as aggregation-caused quenching (ACQ) effect that hinders the fabrication of highly emissive fluorescent nanoparticles. In this work, we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission (AIE) in far-red/near-infrared (FA/NIR) region. A conventional ACQ-characteristic fluorescent dye, 3,4:9,10-tetracarboxylic perylene bisimide (PBI), is converted into an AIE fluorogen through attaching two tetraphenylethylene (TPE) moieties. The fluorescent dots with surface folic acid groups are fabricated from PBI derivative (DTPEPBI), showing specific targeting effect to folate receptor-overexpressed cancer cells. In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention (EPR) effect and folate receptor-mediated active targeting effect. The low cyto-toxicity, good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.展开更多
Fluorescent probes play a key role in modern biomedical research.As compared to inorganic quantum dots(QDs)composed with heavy metal elements,organic dye-based fluorescent nanoparticles have higher biocompatibility an...Fluorescent probes play a key role in modern biomedical research.As compared to inorganic quantum dots(QDs)composed with heavy metal elements,organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety.However,traditional organic fluorophores tend to quench fluorescence upon aggregation,which is known as aggregation-caused quenching(ACQ)effect that hinders the fabrication of highly emissive fluorescent nanoparticles.In this work,we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission(AIE)in far-red/near-infrared(FA/NIR)region.A conventional ACQ-characteristic fluorescent dye,3,4:9,10-tetracarboxylic perylene bisimide(PBI),is converted into an AIE fluorogen through attaching two tetraphenylethylene(TPE)moieties.The fluorescent dots with surface folic acid groups are fabricated from PBI derivative(DTPEPBI),showing specific targeting effect to folate receptor-overexpressed cancer cells.In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention(EPR)effect and folate receptor-mediated active targeting effect.The low cytotoxicity,good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.展开更多
Multi-walled carbon nanotubes （MWNTs） and chitosan （CS） composite rods with layer-by-layer structure were prepared via in situ precipitation method. On the one hand, some MWNTs fragments with open tips played the ...Multi-walled carbon nanotubes （MWNTs） and chitosan （CS） composite rods with layer-by-layer structure were prepared via in situ precipitation method. On the one hand, some MWNTs fragments with open tips played the role of nuclear agent to improve the crystallinity of CS. On the other hand, MWNTs embedded in CS matrix to absorb energy when the composite rods were destroying. Nanotubes pulled out from CS matrix, and lots of holes remained, so MWNTs could endure external stress effectively. The bending strength and bending modulus of CS/MWNTs rods （100/0.5, W/W） arrived at 130.7 MPa and 4.4 GPa respectively, increased by 34.3% and 7.3% compared with those of pure CS rods. Consequently, CS/MWNTs composite rods with excellent mechanical properties could be a novel device used for bone fracture internal fixation.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50573065 & 50873086)the Natural Science Foundation of Zhejiang Province (Grant No. Z406018)
文摘We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.
基金supported by the National Natural Science Foundation of China (50333020 & 50773070)National Basic Research Program of China ((973 Program,2009CB930104)+1 种基金China Postdoctoral Science Foundation (20100480085)Grand Science and Technology Special Project of Zhejiang Province (2008C11087)
文摘Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.
基金partially supported by the National Natural Science Foundation of China(51173018)National Basic Research Program of China(2013CB834704,2011CB935702)+1 种基金the Fundamental Research Funds for the Central Universities,RPC Grants of HKUST(RPC11SC09)the Research Grants Council of Hong Kong(HKUST2/CRF/10)
文摘Two derivatives of tetraphenylethene (TPE) were synthesized through one step cross McMurry coupling reaction. Both luminogens exhibit aggregation-induced emission (AIE) and crystallization induced emission enhancement (CIEE). The emissions of both luminogens could be switched between blue and green through reversible modulation of morphology with thermal, organic solvent fuming and mechanical stimuli. Thus we provide a possible design strategy for emission switching materials.
基金supported by the National Natural Science Foundation of China(No.50773070)the Key Basic Research Development Plan(Project 973) of China(No.2005CB623902)+1 种基金Grand Science and Technology Special Project of Zhejiang Province(No.2008C11087)Science and Technology Project of Zhejiang Province(No.2006C33067)
文摘In an effort to develop biomaterials to meet guided tissue regeneration （GTR） standards for periodontal tissue recovery, a homogeneous and transparent chitosan （CS）/hydroxyapatite （HA） membrane with potential applications as GTR barrier in periodontal therapy has been prepared via in situ compositing. The membrane has been designed to have a smoothrough asymmetric structure that meets the demand for GTR. Component and morphology of the membrane are characterized by XRD and SEM. It can be indicated that HA was in situ synthesized uniformly in the CS membrane. Mechanical experiments of the membranes with various HA contents show that their tensile strengths are adequate for periodontal therapy. Biological properties of the membrane have been performed by cell toxicity assays, hemolysis tests and animal experiments. Results indicate that the membrane has good biocompatibility and inductive effect for cell growth. Therefore this membrane can be potentially applied as GTR barrier membrane for periodontal tissue regeneration.
基金partially supported by the National Natural Science Foundation of China (21074113,20634020 & 20974028)the National Basic Research Program of China (973 Program,2009CB623605)+1 种基金the Research Grants Council of Hong Kong (603509 & HKUST2/CRF/10)the University Grants Committee of Hong Kong (AoE/P-03/08)
文摘We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA （P2） was derived by desilylation of the pristine PA with trimethylethynylsilane side chains （P1）. P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane （M） under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps （from P1 to P3 via precursor P2） and one-pot （from P1 to P3 without separation and purification of P2） were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.
基金the Agency for Science Technology and Research Joint Council and Institute of Materials Research and Engineering of Singapore (IMRE/13-8P1104)the Singapore National Research Foundation (R-279-000-390-281)+1 种基金the Research Grants Council of Hong Kong (603509, HKUST2/CRF/10, 604711, N_HKUST620/11)the Guangdong Innovative Research Team Program (201101C0105067115)
文摘Fluorescent probes play a key role in modern biomedical research. As compared to inorganic quantum dots (QDs) composed with heavy metal elements, organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety. However, traditional organic fluorophores tend to quench fluorescence upon aggregation, which is known as aggregation-caused quenching (ACQ) effect that hinders the fabrication of highly emissive fluorescent nanoparticles. In this work, we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission (AIE) in far-red/near-infrared (FA/NIR) region. A conventional ACQ-characteristic fluorescent dye, 3,4:9,10-tetracarboxylic perylene bisimide (PBI), is converted into an AIE fluorogen through attaching two tetraphenylethylene (TPE) moieties. The fluorescent dots with surface folic acid groups are fabricated from PBI derivative (DTPEPBI), showing specific targeting effect to folate receptor-overexpressed cancer cells. In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention (EPR) effect and folate receptor-mediated active targeting effect. The low cyto-toxicity, good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.
文摘Fluorescent probes play a key role in modern biomedical research.As compared to inorganic quantum dots(QDs)composed with heavy metal elements,organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety.However,traditional organic fluorophores tend to quench fluorescence upon aggregation,which is known as aggregation-caused quenching(ACQ)effect that hinders the fabrication of highly emissive fluorescent nanoparticles.In this work,we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission(AIE)in far-red/near-infrared(FA/NIR)region.A conventional ACQ-characteristic fluorescent dye,3,4:9,10-tetracarboxylic perylene bisimide(PBI),is converted into an AIE fluorogen through attaching two tetraphenylethylene(TPE)moieties.The fluorescent dots with surface folic acid groups are fabricated from PBI derivative(DTPEPBI),showing specific targeting effect to folate receptor-overexpressed cancer cells.In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention(EPR)effect and folate receptor-mediated active targeting effect.The low cytotoxicity,good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.
基金supported by the National Natural Science Foundation of China(No.50773070)the Key Basic Research Development Plan(Project 973) of China(No.2005CB623902)Grand Science and Technology Special Project of Zhejiang Province(No.2008C11087).
文摘Multi-walled carbon nanotubes （MWNTs） and chitosan （CS） composite rods with layer-by-layer structure were prepared via in situ precipitation method. On the one hand, some MWNTs fragments with open tips played the role of nuclear agent to improve the crystallinity of CS. On the other hand, MWNTs embedded in CS matrix to absorb energy when the composite rods were destroying. Nanotubes pulled out from CS matrix, and lots of holes remained, so MWNTs could endure external stress effectively. The bending strength and bending modulus of CS/MWNTs rods （100/0.5, W/W） arrived at 130.7 MPa and 4.4 GPa respectively, increased by 34.3% and 7.3% compared with those of pure CS rods. Consequently, CS/MWNTs composite rods with excellent mechanical properties could be a novel device used for bone fracture internal fixation.
