Artificial Cells, Blood Substitutes and Biotechnology, 2003
Chitosan was covalently coupled to type I collagen by using 1-ethyl-3-(3-dimethylaminopropyl)-car... more Chitosan was covalently coupled to type I collagen by using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide in morpholinoethane sulfonic acid buffer. The physico-chemical characteristics of the collagen/chitosan matrices (CCM) were evaluated by electron spectroscopy and tensile mechanical strength. The platelet deposition and endothelial cell culture experiments show that the CCM have good cell compatibility and excellent blood compatibility. The results suggest that the CCM creates an appropriate environment for the regeneration of endothelial cells and are promising candidates as biomaterials for the tissue regeneration scaffolds.
ABSTRACT New cholesterol-saccharide conjugate gelator N-cholesteryl succinyl glucosamine (1) was ... more ABSTRACT New cholesterol-saccharide conjugate gelator N-cholesteryl succinyl glucosamine (1) was synthesized and its gelation ability was evaluated in organic solvents in this study. It could gelate 1-butanol, iso-butanol, 4-heptanol, cyclohexanol and 1-octanol under the concentration of 5.0 mg/mL. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), circular dichroism (CD) and small-angle X-ray diffraction (SAXRD) were used to analyze the aggregation mode of 1 in the organogel phase. 1 exhibited a fibrous structure composed of thin micellar fibrils with ca.9∼10 nm diameters and these fibrils were packed into a disordered hexagonal mesophase structure with an interlayer distance of 8.01 nm. CD spectra showed that 1 adopted the helical arrangement in the aggregation. A hierarchical self-assembly model was proposed to explain the transition from molecular to primary and secondary structure. Moreover, sol-gel polymerization of tetraethoxysilane (TEOS) was carried out using 1 in the gel phase. The silica obtained from the 1 + 1-butanol gel showed the tubular structure with ca. 100 nm outer diameter.
Single-walled carbon nanotube (SWNT) is a pseudo-one-dimensional nanostructure capable of carryin... more Single-walled carbon nanotube (SWNT) is a pseudo-one-dimensional nanostructure capable of carrying/displaying a large number of bioactive molecules and species in aqueous solution. In this work, a series of dendritic -Dgalactopyranosides and R-D-mannopyranosides with a terminal amino group were synthesized and used for the functionalization of SWNTs, which targeted the defect-derived carboxylic acid moieties on the nanotube surface. The higher-order sugar dendrons were more effective in the solubilization of SWNTs, with the corresponding functionalized nanotube samples of improved aqueous solubility characteristics. Through the functionalization, the nanotube apparently serves as a unique scaffold for displaying multiple copies of the sugar molecules in pairs or quartets. Results on the synthesis and characterization of these sugar-functionalized SWNTs and their biological evaluations in binding assays with pathogenic Escherichia coli and with Bacillus subtilis (a nonvirulent simulant for Bacillus anthracis or anthrax) spores are presented and discussed.
The purpose of this research was to develop polylactic-co-glycolic acid (PLGA) nanospheres surfac... more The purpose of this research was to develop polylactic-co-glycolic acid (PLGA) nanospheres surface modified with chitosan (CS). Mitoxantrone-(MTO-) loaded PLGA nanospheres were prepared by a solvent evaporation technique. The PLGA nanospheres surface was modified with CS by two strategies (adsorption and covalent binding). PLGA nanospheres of 248.4 ± 21.0 nm in diameter characterized by the laser light scattering technique, scanning electron microscopy (SEM) are spherical and its drug encapsulation efficiency is 84.1 ± 3.4%. Zeta potential of unmodified nanospheres was measured to be negative −21.21 ± 2.13 mV. The positive zeta potential of modified nanospheres reveals the presence of CS on the surface of the modified nanospheres. Modified nanospheres were characterized for surface chemistry by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR). FT-IR spectra exhibited peaks at 3420 cm −1 and 1570 cm −1 , XPS spectra shows the N 1s (atomic orbital 1s of nitrogen) region of the surface of the nanospheres, corresponding to the primary amide of CS. In vitro drug release demonstrated that CS-modified nanospheres have many advantages such as prolonged drug release property and decreased the burst release over the unmodified nanospheres, and the modified nanospheres by covalent binding method could achieve the release kinetics of a relatively constant release. These data demonstrate high potential of CS-modified PLGA nanospheres for the anticancer drug carrier.
Artificial Cells, Blood Substitutes and Biotechnology, 2008
A water-in-oil-in-oil double-emulsion solvent/evaporation method was used to prepare vincristine ... more A water-in-oil-in-oil double-emulsion solvent/evaporation method was used to prepare vincristine sulfate (VCR) loaded poly(lactide-co-glycolide) microspheres, and then VCR microspheres were mixed with collagen and (or) chitosan swelling solution and lyophilized to form polymeric films. The films were cross-linked by 0.3% glutaraldehyde (GA). Encapsulation efficiency and release kinetics of VCR microspheres were determined, as well as release kinetics and in vitro degradation of the film. The rate of VCR release from the film submerged in PBS (pH 6.8) and the content were measured by high-performance liquid chromatography (HPLC). The physichemical properties of the film, such as surface morphology, mechanical function, and differential scanning calorimetry, were also measured. VCR was released from the film in a prolonged period and the initial burst release of the film was less significant. In the degradation experiment, the film containing chitosan degraded more slowly than that without chitosan. The films comprising collagen and chitosan could achieve the release kinectics of a relatively constant release. It has a promising future.
Artificial Cells, Blood Substitutes and Biotechnology, 2006
A three-dimensional biodegradable porous scaffold plays a vital role in a tissue engineering appr... more A three-dimensional biodegradable porous scaffold plays a vital role in a tissue engineering approach. Collagen, chitosan and hyaluronan (HA) are natural extracellular matrix (ECM) or similarity, and may provide appropriate environment for the generation of cartilage-like tissue. In this study, we prepared a collagen/chitosan/HA tri-copolymer porous scaffold by freezing and lyophilization to evaluate physico-chemical properties of the tri-copolymer scaffold and its capacity to sustain chondrocytes proliferation and differentiation in vitro. The results show that the mechanical strength, the resistance to enzymatic degradation, and the waterblinding capacity were improved when chitosan and hyaluronan were incorporated into a collagen scaffold. After 21 days of culture, the porous scaffold had been surfaced with cartilaginous tissue. DNA and glycosaminoglycan (GAG) contents were significantly higher during culture periods in collagen/ chitosan/hyaluronan matrix compared to collagen alone matrix, and most seeded cells preserved the chondrocytic phenotype during culture within the scaffold. The collagen/chitosan/hyaluronan tri-copolymer scaffold has potential applications in a cartilage tissue engineering scaffold field.
... Qiqing Zhang,; Lingrong Liu,; Lei Ren,; Fujun Wang. ... Correspondence: Qiqing Zhang, Institu... more ... Qiqing Zhang,; Lingrong Liu,; Lei Ren,; Fujun Wang. ... Correspondence: Qiqing Zhang, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, PO Box 25(204), Tianjin, 300192, People's Republic of China. Publication History. ...
Willow or poplar catkins were carbonized to prepare carbon microtubes (CMTs) due to their natural... more Willow or poplar catkins were carbonized to prepare carbon microtubes (CMTs) due to their natural micro-tubular structure. After carbonization at temperatures of 550-950°C, CMTs with outer and inner diameters of 4-8 and 3-7 lm were obtained. In addition to having a large and accessible inner tube, a small amount of nitrogen ($1.8 at.%) and phosphorus ($0.4 at.%) dopants cause CMTs prepared at 750°C to be a cheap metal-free catalyst with good catalytic activity in the oxygen reduction reaction.
Artificial Cells, Blood Substitutes and Biotechnology, 2003
Chitosan was covalently coupled to type I collagen by using 1-ethyl-3-(3-dimethylaminopropyl)-car... more Chitosan was covalently coupled to type I collagen by using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide in morpholinoethane sulfonic acid buffer. The physico-chemical characteristics of the collagen/chitosan matrices (CCM) were evaluated by electron spectroscopy and tensile mechanical strength. The platelet deposition and endothelial cell culture experiments show that the CCM have good cell compatibility and excellent blood compatibility. The results suggest that the CCM creates an appropriate environment for the regeneration of endothelial cells and are promising candidates as biomaterials for the tissue regeneration scaffolds.
ABSTRACT New cholesterol-saccharide conjugate gelator N-cholesteryl succinyl glucosamine (1) was ... more ABSTRACT New cholesterol-saccharide conjugate gelator N-cholesteryl succinyl glucosamine (1) was synthesized and its gelation ability was evaluated in organic solvents in this study. It could gelate 1-butanol, iso-butanol, 4-heptanol, cyclohexanol and 1-octanol under the concentration of 5.0 mg/mL. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), circular dichroism (CD) and small-angle X-ray diffraction (SAXRD) were used to analyze the aggregation mode of 1 in the organogel phase. 1 exhibited a fibrous structure composed of thin micellar fibrils with ca.9∼10 nm diameters and these fibrils were packed into a disordered hexagonal mesophase structure with an interlayer distance of 8.01 nm. CD spectra showed that 1 adopted the helical arrangement in the aggregation. A hierarchical self-assembly model was proposed to explain the transition from molecular to primary and secondary structure. Moreover, sol-gel polymerization of tetraethoxysilane (TEOS) was carried out using 1 in the gel phase. The silica obtained from the 1 + 1-butanol gel showed the tubular structure with ca. 100 nm outer diameter.
Single-walled carbon nanotube (SWNT) is a pseudo-one-dimensional nanostructure capable of carryin... more Single-walled carbon nanotube (SWNT) is a pseudo-one-dimensional nanostructure capable of carrying/displaying a large number of bioactive molecules and species in aqueous solution. In this work, a series of dendritic -Dgalactopyranosides and R-D-mannopyranosides with a terminal amino group were synthesized and used for the functionalization of SWNTs, which targeted the defect-derived carboxylic acid moieties on the nanotube surface. The higher-order sugar dendrons were more effective in the solubilization of SWNTs, with the corresponding functionalized nanotube samples of improved aqueous solubility characteristics. Through the functionalization, the nanotube apparently serves as a unique scaffold for displaying multiple copies of the sugar molecules in pairs or quartets. Results on the synthesis and characterization of these sugar-functionalized SWNTs and their biological evaluations in binding assays with pathogenic Escherichia coli and with Bacillus subtilis (a nonvirulent simulant for Bacillus anthracis or anthrax) spores are presented and discussed.
The purpose of this research was to develop polylactic-co-glycolic acid (PLGA) nanospheres surfac... more The purpose of this research was to develop polylactic-co-glycolic acid (PLGA) nanospheres surface modified with chitosan (CS). Mitoxantrone-(MTO-) loaded PLGA nanospheres were prepared by a solvent evaporation technique. The PLGA nanospheres surface was modified with CS by two strategies (adsorption and covalent binding). PLGA nanospheres of 248.4 ± 21.0 nm in diameter characterized by the laser light scattering technique, scanning electron microscopy (SEM) are spherical and its drug encapsulation efficiency is 84.1 ± 3.4%. Zeta potential of unmodified nanospheres was measured to be negative −21.21 ± 2.13 mV. The positive zeta potential of modified nanospheres reveals the presence of CS on the surface of the modified nanospheres. Modified nanospheres were characterized for surface chemistry by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR). FT-IR spectra exhibited peaks at 3420 cm −1 and 1570 cm −1 , XPS spectra shows the N 1s (atomic orbital 1s of nitrogen) region of the surface of the nanospheres, corresponding to the primary amide of CS. In vitro drug release demonstrated that CS-modified nanospheres have many advantages such as prolonged drug release property and decreased the burst release over the unmodified nanospheres, and the modified nanospheres by covalent binding method could achieve the release kinetics of a relatively constant release. These data demonstrate high potential of CS-modified PLGA nanospheres for the anticancer drug carrier.
Artificial Cells, Blood Substitutes and Biotechnology, 2008
A water-in-oil-in-oil double-emulsion solvent/evaporation method was used to prepare vincristine ... more A water-in-oil-in-oil double-emulsion solvent/evaporation method was used to prepare vincristine sulfate (VCR) loaded poly(lactide-co-glycolide) microspheres, and then VCR microspheres were mixed with collagen and (or) chitosan swelling solution and lyophilized to form polymeric films. The films were cross-linked by 0.3% glutaraldehyde (GA). Encapsulation efficiency and release kinetics of VCR microspheres were determined, as well as release kinetics and in vitro degradation of the film. The rate of VCR release from the film submerged in PBS (pH 6.8) and the content were measured by high-performance liquid chromatography (HPLC). The physichemical properties of the film, such as surface morphology, mechanical function, and differential scanning calorimetry, were also measured. VCR was released from the film in a prolonged period and the initial burst release of the film was less significant. In the degradation experiment, the film containing chitosan degraded more slowly than that without chitosan. The films comprising collagen and chitosan could achieve the release kinectics of a relatively constant release. It has a promising future.
Artificial Cells, Blood Substitutes and Biotechnology, 2006
A three-dimensional biodegradable porous scaffold plays a vital role in a tissue engineering appr... more A three-dimensional biodegradable porous scaffold plays a vital role in a tissue engineering approach. Collagen, chitosan and hyaluronan (HA) are natural extracellular matrix (ECM) or similarity, and may provide appropriate environment for the generation of cartilage-like tissue. In this study, we prepared a collagen/chitosan/HA tri-copolymer porous scaffold by freezing and lyophilization to evaluate physico-chemical properties of the tri-copolymer scaffold and its capacity to sustain chondrocytes proliferation and differentiation in vitro. The results show that the mechanical strength, the resistance to enzymatic degradation, and the waterblinding capacity were improved when chitosan and hyaluronan were incorporated into a collagen scaffold. After 21 days of culture, the porous scaffold had been surfaced with cartilaginous tissue. DNA and glycosaminoglycan (GAG) contents were significantly higher during culture periods in collagen/ chitosan/hyaluronan matrix compared to collagen alone matrix, and most seeded cells preserved the chondrocytic phenotype during culture within the scaffold. The collagen/chitosan/hyaluronan tri-copolymer scaffold has potential applications in a cartilage tissue engineering scaffold field.
... Qiqing Zhang,; Lingrong Liu,; Lei Ren,; Fujun Wang. ... Correspondence: Qiqing Zhang, Institu... more ... Qiqing Zhang,; Lingrong Liu,; Lei Ren,; Fujun Wang. ... Correspondence: Qiqing Zhang, Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, PO Box 25(204), Tianjin, 300192, People's Republic of China. Publication History. ...
Willow or poplar catkins were carbonized to prepare carbon microtubes (CMTs) due to their natural... more Willow or poplar catkins were carbonized to prepare carbon microtubes (CMTs) due to their natural micro-tubular structure. After carbonization at temperatures of 550-950°C, CMTs with outer and inner diameters of 4-8 and 3-7 lm were obtained. In addition to having a large and accessible inner tube, a small amount of nitrogen ($1.8 at.%) and phosphorus ($0.4 at.%) dopants cause CMTs prepared at 750°C to be a cheap metal-free catalyst with good catalytic activity in the oxygen reduction reaction.
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