Papers by Keyword: Carboxymethyl Chitosan

Abstract: A new antibacterial acellular dermal matrix (AADM) dressing can not only resist infection, but also accelerate wound healing. AADM was prepared by SDS (0.40%), trypsin (0.40%) and keratin (0.30%), and then cross-linked with carboxymethyl chitosan (1%) with glutaraldehyde, whose tensile strength (MPa) is 10.66, thickness (mm), 0.53, the rate of permeable steam (g • m^-2 • 24h^-1), 3640, porosity (%), 81, degradation time in vitro (h), 24.33, pH, 6.5, and the average inhibition rate, more than 70%. At the same time, scanning electron microscopy showed that the structure of AADM was evacuated and the pores were interconnected. On such basis, a conclusion was drawn: the properties of AADM has been sharply increased, compared with acellular dermal matrix, which cannot resist infection, and the new antibacterial acellular dermal matrix completely meets the clinical requirements for burn dressings.

Abstract: Carboxymethyl chitosan (CAS) was obtained by carboxymethylation of chitosan (CS).The Ag⁺-CAS,TiO₂-CAS and Ag⁺-TiO₂-CAS were prepared by introducing AgNO₃ and nanometre TiO₂ solution into the product obtained the previous step. The structures of samples were characterized by IR, XRD, SEM etc. The properties of cruor and hemostasis were studied by biological experiment. The results showed that there were characteristic absorption peaks of carboxymethyl chitosan sodium salt around 3423cm^-1 and 1380cm^-1 in the IR spectra of modified carboxymethyl chitosan. The XRD showed it was metals Crystalline. The average diameter of CAS was about 14.8nm, the Ag⁺ was 143.5nm, nanometre TiO₂ was 267.2nm and all of them were homodisperse. The properties of crour and hemostasis of Ag⁺-TiO₂-CAS were superior to Ag⁺-CAS and TiO₂-CAS, while the Ag⁺-CAS and TiO₂-CAS were also have an advantage over CAS.

Abstract: In this paper,under alkaline conditions,with chloroacetic acid to modify chitosan,obtained carboxymethyl chitosan. At pH<7 conditions,the obtained carboxymethy chitosan respectively were reacted with calcium chloride solution,zinc chloride solution,after fully reacted,obtained carboxymethyl chitosan calcium and carboxymethyl chitosan zinc .Through infrared spectrum,X-ray diffraction and scanning electron microscopy (sem) analysis means,the structure of the products were characterized.Through the cutting of mice tail hemostasia test ,study the performance of the product.The results showed that the water solubility of carboxymethyl chitosan is better than that of chitosan and with excellent performance,and the performance of carboxymethyl chitosan calcium and carboxymethyl chitosan zinc was better than that of carboxymethyl chitosan.

Abstract: In this study, we synthesized carboxymethyl chitosan-graft-poly(ε-caprolactone) (CMCS-g-PCL) by grafting ε-CL onto the hydroxyl groups of CMCS via ring-opening polymerization. The graft copolymers were characterized by ¹H NMR spectroscopy and thermogravimetric analysis (TGA). Then use the graft copolymer to produce the micelle by solvent-evaporation method. The DLS and TEM were utilized to evaluate the particle size and morphology and showed that the micelles were in a well-defined spherical shape with a uniform size distribution. The results indicated that the size of range is below 200 nm and could be used as drug carrier and have better active cellular uptake.

Abstract: This study investigates the effectiveness of adding carboxymethyl chitosan during steam cooking as an adsorbent for detoxifying paralytic shellfish poisoning toxins (PSP toxins) in the scallop Chlamys nobilis. Toxin analysis using a mouse bioassay test and hydrophilic interaction liquid chromatography–tandem mass spectrometry method (LC–MS) showed that most of the PSP toxins (>80%) were contained in the visceral compartment of the raw scallops. Overall, 82.2Mu/100g of PSP toxins were released from scallop tissues during steaming. The toxicity of the soup steamed with 0.1%, 0.3%, 0.6%, 1.0% and 1.5% carboxymethyl chitosan decreased the toxin content by 35.6%, 44%, 48.4%, 53.3% and 56.9% (p<0.005), respectively. The relative PSP toxin content in the raw adductor muscle was comparable to those after steaming or steaming with carboxymethyl chitosan (p > 0.05).The PSP toxin concentrations in the adductor muscles, gills + mantle and visceral compartments steamed with 0.1%, 0.3%, 0.6%, 1% and 1.5% carboxymethyl chitosan were not significantly different from those in the corresponding raw samples. The LC–MS analysis showed that the adsorbance of carboxymethyl chitosan for each of the PSP toxins was positive correlation with concentration, although the uptake efficiency of each toxin was different. The reduction in toxin content of all analyzed toxins reached 45.6%, 30.2%, 44.5%, 55.9% and 37.6% under the corresponding carboxymethyl chitosan concentrationsis.

Abstract: Carboxymethyl chitosan aerogel was prepared by freeze-drying method with glutaraldehyde as crosslinking agent. The effect of different concentrations of crosslinking agent and solvent on the gel time and porosity was investigated. The absorption capacity of aerogel was investigated with different oils (gasoline, diesel oil, peanut oil, dimethyl silicone). The results were shown as 1) the highest porosity of the aerogel was 95.01% and the lowest density was 0.026g/cm³. 2) The optimum preparation condition was the concentration of crosslinking agent 20%, the solvent concentration 2%. Oil absorption capacity of the aerogel was up to the maximum of 28.6g/g (to dimethyl silicone), which was higher than to the other three oils. This work offered a preparation method for the high porosity, high oil-absorbing massive carboxymethyl chitosan aerogel and revealed its potential application in the treatment of oil pollution.

Abstract: To improve carboxymethylation reaction, chitosan as reactant was activated to change its morphology and compact structure. The crystallization properties of chitosan before and after activation were characterized by X-ray diffraction analysis. Different preparation methods were compared using activated, powdery or flake chitosan as reactants, respectively. And the influences of reaction time and temperature on the yield, the intrinsic viscosity and the degree of substitution of carboxymethyl chitosan were also investigated. We found that, the activation treatment changed the crystallization properties of chitosan, which greatly accelerated the subsequent carboxymethylation reaction; and higher yield of carboxymethyl chitosan with considerable intrinsic viscosity was obtained under the reaction conditions of a shorter time and a milder temperature.

Abstract: In this paper, the cross-linking injection hydrogel were synthesized by EDC crosslinker and Carboxymethyl chitosan (CMCS)/Human-like collagen (HLC). Cytotoxicity was assessed by Methylthiazolydiphenyl-tetrazolium bromide (MTT) assay which indicated that the hydrogels was non-toxic to the BHK21 cell .Chondrocyct-encapsulation of this hydrogel were studied in order to asses the cells compatibility of the injection gel. The result showed that the material has no cytotoxicity to the cells and promoted cell adhesion and proliferation. Injected those hydrogels into mice subcutaneous , the following parameters were evaluated: inflammatory response, vascularization, new hypoderm generation. After 2,4,12,and 24 weeks of healing, the rats were sacrilifced suggested that gels in animals did not induce inflammation obvious, vessel bestrid the material after 4 weeks injection, new hypoderm generated in 12 weeks and packaged the hydrogels after 24 weeks. Consequently the gels are promised for the application in the biomaterials area.

Abstract: In this paper, the cross-linking hydrogels were synthesized by EDC crosslinker and Carboxymethyl chitosan (CMCS)/Human-like collagen (HLC). The morphology of the hydrogels was observed by scanning electron microscope (SEM). The important performance of these hydrogels is biodegradation which was assessed in two ways: (1) Through enzyme solution experiment in vitro , investigating in vitro degradation property. (2) Injecting the hydrogels to mice subcutaneous , after 2,4,12,and 24 weeks of healing ,the rats were sacrificed and explanted specimens were prepared for histology analysis. Investigating degradation time in vitro and in vivo , and studying the histology .HLC hydrogels degradation time gets eight to ten months, in addition has good compatibility of the histological performances. The hydrogels are promised for the applications in the biomaterials area.

Abstract: Hydrogels were prepared from carboxymethyl chitosan (CMCS)/Human-like collagen(HLC) by S-acetylmercaptosuccinic anhydride(SAMSA) crosslinker. Fourier transform infrared (FTIR) spectroscopy indicated that there exactly existed interaction HLC, carboxymethyl chitosan and SAMSA. The morphology of the hydrogels was observed by scanning electron microscope (SEM). The equilibrium swelling ratio was also evaluated. Cell culture results showed that these hydrogels were good in promoting the cell attachment and proliferation. The hydrogels are promised for the applications in the biomaterials area.