A sensitive electrochemical biosensor based on Aflatoxin-Oxidase (AFO) was developed for detection of sterigmatocystin (ST). The enzyme was immobilized on chitosan-single-walled carbon nanotubes (CS-SWCNTs) hybrid film, which attached to the poly-o-phenylenediamine (POPD)-modified Au electrode. The fabricated procedures of the biosensor were characterized with atomic force microscopy (AFM), fourier transform-infrared spectroscopy (FT-IR), and electrochemical impedance spectroscopy (EIS). The cyclic voltammetric results of the biosensor indicated that AFO exhibited a surface-controlled and quasi-reversible electrochemical redox behavior with a formal potential of -0.436 V (vs. Ag/AgCl) in 0.1 mol/L PBS (pH 7.0), which resulted from the direct electron transfer between entrapped AFO and the underlying electrode. The enzymatic electrode exhibited an excellent electrocatalytic response to ST. The linear range of ST determination was from 10 ng/mL to 310 ng/mL with correlation coefficient of 0.997, the detection limit was 3 ng/mL (S/N=3), and the response time was less than 10 seconds. The apparent Michaelis-Menten constant (K(M)app) was estimated to be 7.13 micromol/L. The biosensor had the advantages of good repeatability and stability, remaining 85.6% of its original current value after storage at 4 degrees C for a month, and the RSD for 11 replicate determination of 20 ng/mL ST was 3.9%. This AFO/CS-SWCNTs/POPD/Au modified electrode showed high selectivity and sensitivity in real sample analysis, giving values of recovery in the range of 87.6%-105.5%. The proposed method can be applied to the determination of ST in real samples with satisfactory results.
Aflatoxins ; Biosensing Techniques ; methods ; Chitosan ; chemistry ; Electrons ; Nanotubes, Carbon ; Oxidation-Reduction ; Oxidoreductases ; Phenylenediamines ; chemistry ; Sterigmatocystin ; analysis

OBJECTIVETo study the efficacy and safety of plasma-perfusion with a novel aminated chitosan on liver failure in a canine model.

METHODSA canine model of liver failure was established. Plasma-perfusion with a novel aminated chitosan was performed on those dogs. Blood pressure and body temperature during plasma-perfusion were monitored. Total plasma bilirubin, direct bilirubin and indirect bilirubin at the entrance and exit of a column before and after plasma-perfusion and at the time of 15, 30, 60, and 120 min during plasma-perfusion were examined. Blood alanine aminotransferase, aspartate aminotransferase, ammonia, plasma prothrombin time, electrolytes and other blood parameters were examined before and after the plasma-perfusion.

RESULTSAfter the plasma-perfusion, total bilirubin decreased from 177.4+/-18.1 to 46.1+/-3.7 (P less than 0.05), direct bilirubin decreased from 124.2+/-10.3 to 30.5+/-1.7 (P less than 0.05), indirect bilirubin decreased from 53.2+/-2.8 to 15.6+/-2.0 (P less than 0.05). Compared at the entrance of the column, there were significant decreases in the levels of total bilirubin, direct bilirubin and indirect bilirubin of plasma at the exit of the column at the times of 15 and 30 min during plasma-perfusion (P less than 0.05); there were no further significant decreases at 60 and 120 min (P more than 0.05). Compared with pre-plasma-perfusion, there were significant decreases in the levels of blood alanine aminotransferase, aspartate aminotransferase, and ammonia (P less than 0.05); the plasma prothrombin time was significantly increased (P less than 0.05), the electrolytes, hematocrit level, platelet count, and white cell count were not affected significantly by the perfusion (P more than 0.05); blood pressure and body temperature were not affected significantly during the plasma-perfusion.

CONCLUSIONPlasma-perfusion with a novel aminated chitosan resin is an effective and safe method for treating liver failure in this canine model.

Animals ; Bilirubin ; blood ; Blood Chemical Analysis ; Chitosan ; blood ; therapeutic use ; Dogs ; Female ; Liver Failure ; therapy ; Male ; Perfusion ; Plasma

The effect of chitosan with different molecular weight and deacetylation degree on blood hemostasis was tested. The experiments found evident alteration of red blood cell morphology and unusual coagglutination between erythrocytes in the anticoagulant blood which was treated by chitosan acetic acid solution. The red blood cells clot formation experiments showed that chitosan with low deacetylation degree (60%-70%) caused more red blood cells to assemble when compared versus chitosan with other deacetylation degrees. The effect of molecular weight between 10(5)-10(6) was not obvious. The thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), and concentration of fibrinogen (FIB) of blood treated by chitosan acetic acid solution were measured. The results proved that the hemostasis property of chitosan acetic acid solution was independent of the platelets and the normal "Cascade-like" coagulation pathway.
Acetic Acid ; chemistry ; pharmacology ; Animals ; Chitosan ; chemistry ; pharmacology ; Fibrinogen ; analysis ; Hemostatics ; chemistry ; pharmacology ; Partial Thromboplastin Time ; Prothrombin Time ; Rabbits ; Thrombin Time

OBJECTIVESTo investigate the effect of chitosan biodegradable external stent (CES) on the early changes of rabbit vein graft (VG).

METHODSRabbit vein grafting models were divided into S group (with perivenous CES) and NS group (without perivenous CES). The VG were harvested in 1 week, 2 weeks, 4 weeks after operation, respectively. The expression of proliferating cell nuclear antigen (PCNA) was used for evaluating the proliferation of the smooth muscle cell (SMC). The thickness, area of neointima and media of the VG were calculated by computer imaging analysis system.

RESULTSCES began to degrade in 2 weeks after operation. The thickness, area of both neointima and media of the VG in S group, increased mildly in 1 week after operation, and kept steady in 1 or 2 weeks after grafting, which was significantly less than NS group (both P < 0.01), then increased mildly in 4 weeks after grafting but still less than NS group (P < 0.05). The expression of PCNA of SMC decreased significantly in comparison with NS group though increasing mildly in four weeks after operation. Both neointimal formation and cell proliferation in the graft wall were significantly reduced by external stenting as compared to the results with unstented grafts.

CONCLUSIONSCES may reduce early intimal and medial hyperplasia, and may be beneficial in improving the long term patency of the VG. The biodegradable characteristics of the CES may influence its effect.

Animals ; Biodegradation, Environmental ; Chitin ; administration & dosage ; analogs & derivatives ; Chitosan ; Female ; Humans ; Hyperplasia ; Male ; Proliferating Cell Nuclear Antigen ; analysis ; Rabbits ; Stents ; Tunica Intima ; pathology ; Veins ; pathology ; transplantation

Various proportions of chitosan/collagen films (70/30% to 95/05%) w/w were prepared and evaluated for its suitability as skin regenerating scaffold. Interactions between chitosan and collagen were studied using Fourier Transform Infrared spectroscopy (FTIR) and Differential Scanning Colorimetry (DSC). Scanning Electron Microscope (SEM) was used to investigate the morphology of the blend. Mechanical properties were evaluated using a Universal Testing Machine (UTM). The chitosan/collagen films were found to swell proportionally with time until it reaches equilibrium. FTIR spectroscopy indicated no chemical interaction between the components of the blends. DSC data indicated only one peak proving that these two materials are compatible at all proportions investigated. SEM micrographs also indicated good homogeneity between these two materials.
Biocompatible Materials/*analysis ; Burns/physiopathology ; Burns/*therapy ; Chitosan/*analysis ; Collagen Type I/*analysis ; *Materials Testing ; Microscopy, Electron, Scanning ; *Occlusive Dressings ; Regeneration/*physiology ; Skin/*physiopathology ; Spectroscopy, Fourier Transform Infrared ; Tensile Strength

OBJECTIVETo evaluate the potency of carboxymethyl chitosan-2, 2' ethylenedioxy bis-ethylamine-folate (CMC-EDBE-FA) on tissue injury, antioxidant status and glutathione system in tissue mitochondria and serum against nicotine-induced oxidative stress in mice.

METHODSCMC-EDBE-FA was prepared on basis of carboxymethyl chitosan tagged with folic acid by covalently linkage through 2, 2' ethylenedioxy bis-ethylamine. Animals were divided into four groups, i.e., control, nicotine (1 mg/kg bw/day), CMC-EDBE-FA (1 mg/kg bw/day) and nicotine (1 mg/kg bw/day) and CMC-EDBE-FA (1 mg/kg bw/day) for 7 days. Levels of lipid peroxidation, oxidized glutathione level, antioxidant enzyme status and DNA damage were observed and compared.

RESULTSThe significantly increase of lipid peroxidation, oxidized glutathione levels and DNA damage was observed in nicotine treated group as compared with control group; those were significantly reduced in CMC-EDBE-FA supplemented group. Moreover, significantly reduced antioxidant status in nicotine treated group was effectively ameliorated by the supplementation of CMC-EDBE-FA. Only CMC-EDBE-FA treated groups showed no significant change as compared with control group; rather than it repairs the tissue damage of nicotine treated group.

CONCLUSIONSThese findings suggest that CMC-EDBE-FA is non-toxic and ameliorates nicotine-induced toxicity.

Animals ; Antioxidants ; chemistry ; pharmacology ; Chitosan ; analogs & derivatives ; chemistry ; pharmacology ; DNA Fragmentation ; drug effects ; Folic Acid ; chemistry ; pharmacology ; Glutathione ; analysis ; metabolism ; Glutathione Transferase ; metabolism ; Male ; Mice ; Nanoparticles ; chemistry ; Nicotine ; toxicity ; Organ Specificity ; Oxidoreductases ; metabolism

Deformities in tissues and organs can be treated by using tissue engineering approach offering the development of biologically functionalized scaffolds from a variety of polymer blends which mimic the extracellular matrix and allow adjusting the material properties to meet the defect architecture. In recent years, research interest has been shown towards the development of chitosan (CS) based biomaterials for tissue engineering applications, because of its minimal foreign body reactions, intrinsic antibacterial property, biocompatibility, biodegradability and ability to be molded into various geometries and forms thereby making it suitable for cell ingrowth and conduction. The present work involves the fabrication of nanofibrous scaffold from CS and poly(vinyl alcohol) blends by free-surface electrospinning method. The morphology and functional characteristics of the developed scaffolds were assessed by field emission scanning electron microscopy and fourier transformed infra-red spectra analysis. The morphological analysis showed the average fiber diameter was 269 nm and thickness of the mat was 200–300 µm. X-ray diffraction study confirmed the crystalline nature of the prepared scaffolds, whereas hydrophilic characteristic of the prepared scaffolds was confirmed by measured contact angle. The scaffolds possess an adequate biodegradable, swelling and mechanical property that is found desirable for tissue engineering applications. The cell study using umbilical cord blood-derived mesenchymal stem cells has confirmed the in vitro biocompatibility and cell supportive property of the scaffold thereby depicting their potentiality for future clinical applications.
Biocompatible Materials ; Chitosan ; Congenital Abnormalities ; Crystallins ; Extracellular Matrix ; Foreign Bodies ; Fourier Analysis ; Fungi ; In Vitro Techniques ; Mesenchymal Stromal Cells ; Methods ; Microscopy, Electron, Scanning ; Nanofibers* ; Polymers ; Tissue Engineering* ; Umbilical Cord ; X-Ray Diffraction

OBJECTIVETo study the result of removing impurity from water-extraction of Gutianquan-capsule with macro-reticular absorbing resin, chitosans clarification, water-extraction and alcohol-precipitation methods.

METHODCoefficient of Unguent of macro-reticular absorbing resin, chitosans clarification method, water-extraction and alcohol-precipitation methods were compared, and qualitative assay of Ginsenoside Rg1, Re, and snide measurement of Ginsenoside Rg1, Ferulic acid, and stability experiment were made.

RESULTCoefficient of Unguent of water-extraction and alcohol-precipitation method was 17.2%, Coefficient of Unguent of chitosans clarification method was 12.8%, and macro-reticular absorbing resin method was 3.1%. They could clarify liquor of water-extraction.

CONCLUSIONChitosans clarification method is suitable for process of Gutianquan-capsule.

Animals ; Capsules ; Chitin ; analogs & derivatives ; Chitosan ; Coumaric Acids ; analysis ; Drug Combinations ; Drug Contamination ; Drug Stability ; Drugs, Chinese Herbal ; administration & dosage ; chemistry ; isolation & purification ; Ginsenosides ; analysis ; Mantodea ; chemistry ; Materia Medica ; administration & dosage ; chemistry ; isolation & purification ; Panax ; chemistry ; Plants, Medicinal ; chemistry ; Technology, Pharmaceutical ; methods

BACKGROUNDDiabetic wound is one of the most serious complications of diabetes mellitus. There are no significantly effective therapies for chronic non-healing diabetes ulcer so far. This study aimed to explore the feasibility of healing impaired wound using artificial dermis constructed with human adipose derived stem cells (ASCs) and poly (L-glutamic acid)/chitosan (PLGA/CS) scaffold in streptozotocin-induced diabetic mice.

METHODSASCs were isolated from fresh human lipoaspirates and expanded ex vivo for three passages, and then cells were seeded onto PLGA/CS scaffold to form artificial dermis. Expression of VEGF and TGFβ1 by ASCs presented in artificial dermis was determined. The artificial dermis was transplanted to treat the 20 mm × 20 mm full-thickness cutaneous wound created on the back of diabetic mice. Wound treated with scaffold alone and without treatment, and wound in normal non-diabetic mice served as control.

RESULTSCells growing within scaffold showed great proliferation potential, depositing abundant collagen matrix. Meanwhile, expression of VEGF and TGF-β1 by seeded ASCs maintained at a consistent high level. After treated with ASC based artificial dermis, diabetic wounds exhibited significantly higher healing rate compared with wounds treated with scaffold alone or without treatment. Histological examination also demonstrated an improvement in cutaneous restoration with matrix deposition and organization. Further quantitative analysis showed that there was a significant increase in dermis thickness and collagen content on artificial dermis treated wounds.

CONCLUSIONASC/PLGA artificial dermis can effectively accelerate diabetic wound healing by promoting angiogenic growth factors and dermal collagen synthesis.

Adipose Tissue ; cytology ; Animals ; Chitosan ; administration & dosage ; Diabetes Mellitus, Experimental ; physiopathology ; Male ; Mice ; Mice, Inbred BALB C ; Polyglutamic Acid ; administration & dosage ; Skin, Artificial ; Stem Cells ; cytology ; Streptozocin ; Tissue Scaffolds ; Transforming Growth Factor beta1 ; analysis ; Vascular Endothelial Growth Factor A ; analysis ; Wound Healing ; drug effects

OBJECTIVETo study the effects of chemoembolization with adriamycin alginate-chitosan microcapsules in the treatment of VX2 carcinoma in the extremity of the rabbit.

METHODSTwenty-four New Zealand white rabbits transplanted with VX2 carcinoma cells into the muscle tissue of the lower right thigh were divided into four groups namely groups A, B, C and D, and received regional infusion from femoral artery. Each group consisted of six rabbits: a group given natural saline (Group A), a group given adriamycin (Group B), a group given blank alginate-chitosan microcapsules (Group C) and a group given adriamycin alginate-chitosan microcapsules (Group D). Three days after treatment, all groups were examined by histology and immunohistochemical detection (TdT-mediated dUTP nick end labeling technique, TUNEL; proliferating cell nuclear antigen, PCNA).

RESULTSThe blood vessels of the tumor were almost embolized by the microcapsules. Extensive necrosis, high level of positive cells in TUNEL (60.85% +/- 5.21%) and low level in PCNA detection with in the tumors were observed in Group D.

CONCLUSIONAdriamycin alginate-chitosan microcapsules can potentially play roles in two respects, 1 to serve as embolizing agents, and 2 to serve as drug delivery vehicles for local release. Chemoembolization with microparticals is an effective treatment of malignant osseous and soft tissue sarcomas in an experimental model.

Alginates ; administration & dosage ; Animals ; Capsules ; Chemoembolization, Therapeutic ; Chitin ; administration & dosage ; analogs & derivatives ; Chitosan ; Disease Models, Animal ; Doxorubicin ; administration & dosage ; Glucuronic Acid ; administration & dosage ; Hexuronic Acids ; administration & dosage ; In Situ Nick-End Labeling ; Neoplasms, Experimental ; drug therapy ; pathology ; Proliferating Cell Nuclear Antigen ; analysis ; Rabbits