Activation of endogenous neurogenesis and angiogenesis by basic fibroblast growth factor-chitosan gel in an adult rat model of ischemic stroke

Attempts have been made to use cell transplantation and biomaterials to promote cell proliferation,differentiation,migration,and survival,as well as angiogenesis,in the context of brain injury.However,whether bioactive materials can repair the damage caused by ischemic stroke by activating endogenous neurogenesis and angiogenesis is still unknown.In this study,we applied chitosan gel loaded with basic fibroblast growth factor to the stroke cavity 7 days after ischemic stroke in rats.The gel slowly released basic fibroblast growth factor,which improved the local microenvironment,activated endogenous neural stem/progenitor cells,and recruited these cells to migrate toward the penumbra and stroke cavity and subsequently differentiate into neurons,while enhancing angiogenesis in the penumbra and stroke cavity and ultimately leading to partial functional recovery.This study revealed the mechanism by which bioactive materials repair ischemic strokes,thus providing a new strategy for the clinical application of bioactive materials in the treatment of ischemic stroke.

Chitosan-based triboelectric materials for self-powered sensing at high temperatures

Although biopolymers have been widely utilized as triboelectric materials for the construction of self-powered sensing systems,the annihilation of triboelectric charges at high temperatures restricts the output signals and sensitivity of the assembled sensors.Herein,a novel chitosan/montmorillonite/lignin(CML)composite film was designed and employed as a tribopositive layer in the assembly of a self-powered sensing system for use under hot conditions(25-70℃).The dense contact surface resulting from the strong intermolecular interaction between biopolymers and nanofillers restrained the volatilization of induced electrons.The optimized CML-TENG delivered the highest open-circuit voltage(V_(oc))of 262 V and maximum instantaneous output power of 429 mW/m^(2).Pristine CH-TENG retained only 39%of its initial Voc at 70℃,whereas the optimized CM_(5)L_(3)-TENG retained 66%of its initial Voc.Our work provides a new strategy for suppressing the annihilation of triboelectric charges at high temperatures,thus boosting the development of self-powered sensing devices for application under hot conditions.

Constructing a biofunctionalized 3D-printed gelatin/sodium alginate/chitosan tri-polymer complex scaffold with improvised biological andmechanical properties for bone-tissue engineering

Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue regeneration.We experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and differentiation.The resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)printing.Morphological studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural stability.The scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue engineering.The tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of gelatin.The enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue regeneration.In vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold surface.In addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its potential for use in bone-tissue engineering.

Using Electrodeposition of Carboxylated Chitosan for Green Preparation of Copper Nanoclusters and Nanocomposite Films

On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.

The ceRNA Network Indicates Its Immune Function in Peripheral Blood Leukocytes of Half-Smooth Tongue Sole(Cynoglossus semilaevis)After Stimulation with Chitosan Oligosaccharide

As an efficient immunostimulant,chitosan oligosaccharide(COS)can enhance the immunity of teleosts;however,the underlying molecular mechanisms still require elucidation.Competing endogenous RNAs(ceRNAs)are vital regulators in the immune response,but their roles in half-smooth tongue sole(Cynoglossus semilaevis)remain unclear.In this study,for the first time,we studied whole-transcriptome expression profiles and analyzed ceRNA networks in peripheral blood leukocytes of half-smooth tongue sole treated with COS.A total of 19 circRNAs(DE-circRNAs),18 miRNAs(DE-miRNAs)and 50 previously identified lncRNAs(DElncRNAs)were differentially expressed after COS stimulation.The DE-lncRNAs and DE-miRNAs targeted numerous immunity-related genes,and were enriched in important pathways,including MAPK and Toll-like receptor signaling pathways,suggesting the immunoregulatory roles of COS.Furthermore,we constructed circRNA-miRNA-mRNA and lncRNA-miRNA-mRNA regulatory networks using DE-circRNAs,DE-miRNAs,DE-lncRNAs,and DE-mRNAs.Additionally,a ceRNA network with immunity-related DEmRNAs was constructed,showing that 3 DE-circRNAs,12 DE-lncRNAs,and 29 DEGs exhibited crosstalk through 9 DE-miRNAs.Intriguingly,a DE-miRNA in the ceRNA network,miR-144-3p,was targeted by DE-lncRNA tnrc6a,and negatively regulated the genes of inhibitor of nuclear factor kappa B kinases(IKKs)(ikbkg,ikbkb,and ikbip)and c3ar1.Ikbkg,ikbkb,and c3ar1 were significantly up-regulated in macrophages stimulated by LPS.It could be inferred that ncRNAs participated in the immune and inflammatory response by acting as ceRNAs after COS stimulation in teleosts.These findings indicate that COS could enhance the immunity of teleosts by regulating ncRNAs,and lay the foundation for further practical application of COS in aquaculture.

Chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor for neurotrophic keratopathy

Neurotrophic keratopathy is a persistent defect of the corneal epithelium,with or without stromal ulceration,due to corneal nerve deficiency caused by a variety of etiologies.The treatment options for neurotrophic keratopathy are limited.In this study,an ophthalmic solution was constructed from a chitosan-based thermosensitive hydrogel with long-term release of murine nerve growth factor(CTH-mNGF).Its effectiveness was evaluated in corneal denervation(CD)mice and patients with neurotrophic keratopathy.In the preclinical setting,CTH-mNGF was assessed in a murine corneal denervation model.CTH-mNGF was transparent,thermosensitive,and ensured sustained release of mNGF for over 20 hours on the ocular surface,maintaining the local mNGF concentration around 1300 pg/mL in vivo.Corneal denervation mice treated with CTH-mNGF for 10 days showed a significant increase in corneal nerve area and total corneal nerve length compared with non-treated and CTH treated mice.A subsequent clinical trial of CTH-mNGF was conducted in patients with stage 2 or 3 neurotrophic keratopathy.Patients received topical CTH-mNGF twice daily for 8 weeks.Fluorescein sodium images,Schirmer’s test,intraocular pressure,Cochet-Bonnet corneal perception test,and best corrected visual acuity were evaluated.In total,six patients(total of seven eyes)diagnosed with neurotrophic keratopathy were enrolled.After 8 weeks of CTH-mNGF treatment,all participants showed a decreased area of corneal epithelial defect,as stained by fluorescence.Overall,six out of seven eyes had fluorescence staining scores<5.Moreover,best corrected visual acuity,intraocular pressure,Schirmer’s test and Cochet-Bonnet corneal perception test results showed no significant improvement.An increase in corneal nerve density was observed by in vivo confocal microscopy after 8 weeks of CTH-mNGF treatment in three out of seven eyes.This study demonstrates that CTH-mNGF is transparent,thermosensitive,and has sustained-release properties.Its effectiveness in healing corneal epithelial defects in all eyes with neurotrophic keratopathy suggests CTH-mNGF has promising application prospects in the treatment of neurotrophic keratopathy,being convenient and cost effective.

Synthesis of chitosan oligosaccharide selenium and its antitumor activity

Background:Polysaccharides have various biological activities;the complexation of polysaccharides with trace element ions can produce synergistic effects,improving the original biological activities of sugars and trace elements.Methods:The preparation process of chitosan oligosaccharide selenium(COSSe)was optimized by the response surface method,followed by a detailed analysis of the resultant compound’s characteristics.The anti-cancer activity of COSSe was studied using the human ovarian cancer cell line SKOV3 as a cell model.Results:The prepared COSSe response surface was well predicted,indicating successful chitosan oligosaccharide binding with selenium.Response surface method analyses identified the optimal synthesis conditions for COSSe:the reaction time of 5.08 h,the reaction temperature of 71.8°C,and mass ratio(Na2SeO3:chitosan oligosaccharide)of 1.02.Under the optimal conditions,the final product,the selenium content,reached 1.302%.The results of cell experiments showed that COSSe significantly inhibited SKOV3 proliferation in a concentration-dependent manner.RNA-seq results showed that chitosan oligosaccharide and COSSe significantly modulated the expression of genes’DNA metabolic processes and cell cycle in SKOV3 cells.Gene enrichment analysis showed the inhibition of the cell cycle,and the results of flow cytometry showed that SKOV3 cells increased in the S phase and decreased in the G2/M phase,with a noted suppression in the protein expression of cyclin-dependent kinase 2(CDK2)and cyclin A1(CCNA1).Conclusion:COSSe has a stronger effect than chitosan oligosaccharide,leading to the arrest of the cell cycle in the S phase.Thus,COSSe may be an effective candidate for the treatment of ovarian cancer.

Encapsulation of Clove Oil Nanoemlusion in Chitosan-Based Nano-Composite: In Vitro and in Vivo Antifungal Activity against Rhizoctonia solani and Sclerotium rolfsii

Rhizoctonia solani Kühn and Sclerotium rolfsii Sacc.are the primary soil-borne plant diseases responsible for sig-nificant reductions in global crop yields.The primary goal of this study was to investigate the antifungal potentials of clove essential oil(CEO),nanoemulsion form(CEONE)and chitosan/nanoemulsion nanocomposite(CS/CEONE)against R.solani and S.rolfsii through in vitro and in vivo trials.Both CEONE and CS/CEONE were prepared and investigated for their physical chemical and morphological characterization.The poisoned medium method was utilized to evaluate the inhibitory effects of CEO,CEONE and CS/CEONE on the mycelial growth and enzymatic activity of R.solani and S.rolfsii.The changes of hyphae of R.solani and S.rolfsii in response to treating with CEONE and CS/CEONE were observed with scanning electron microscope(SEM).The results revealed that CEONE have larger size 86±3 nm and a broader range of PDI 0.121±0.011 on the average.While,CS/CEONE has smaller size of 49±4 nm and narrower PDI of 0.099±0.009.Both nanoemulsions had uniform spherical nanodroplets form and exhibited acidic nature.Fourier Transform Infrared Spectroscopy(FTIR)and UV-Visible Spectroscopy(UV-Vis)verified the successful incorporation of both CS and CEO within the nanoe-mulsion system.The results demonstrated a sustained and prolonged release profile from CS/CEONE for up to 4 days.The inhibitory effect of CEONE and CS/CEONE showed dose-dependent activity against mycelial growth of both fungi.CEONE and CS/CEONE at concentration 500µL/L exhibited the strongest inhibition with a sig-nificant(p<0.05)variation among them with value ranging from 56.11%to 71.94%and 52.2%to 79.2%,respec-tively.Comparing to control,CS/CEONE revealed the highest inhibitory effect against S.rolfsii after 96 h followed by CEONE with value reached 50.6%and 44.1%,respectively.The antifungal activity of the nanoemulsion showed strain–dependent behavior,where S.rolfsii was the most affected.SEM images showed changes in the hyphal structure of S.rolfsii and R.solani resulting from the impact of CEONE and CS/CEONE.Activity of pectinase and cellulase secreted by both fungi was also negatively affected by CEO,CEONE and CS/CEONE at all tested concentrations.Greenhouse trials revealed that increasing the concentrations of CEO,CEONE,and CS/CEONE from 50 to 500μL/L gradually increased their effectiveness in reducing the DI%and DS%of black scurf,stem canker,pre-damping off,and post-damping off diseases on potato.The results suggest that incorporation of CS to CEONE enhanced its activity and can be utilized as a secure and non-toxic nanocomposite.

Chitosan/Sodium Alginate Multilayer pH-Sensitive Films Based on Layer-by-Layer Self-Assembly for Intelligent Packaging

The abuse of plastic food packaging has brought about severe white pollution issues around the world.Developing green and sustainable biomass packaging is an effective way to solve this problem.Hence,a chitosan/sodium alginate-based multilayer film is fabricated via a layer-by-layer(LBL)self-assembly method.With the help of superior interaction between the layers,the multilayer film possesses excellent mechanical properties(with a tensile strength of 50 MPa).Besides,the film displays outstanding water retention property(blocking moisture of 97.56%)and ultraviolet blocking property.Anthocyanin is introduced into the film to detect the food quality since it is one natural plant polyphenol that is sensitive to the pH changes ranging from 1 to 13 in food when spoilage occurs.It is noted that the film is also bacteriostatic which is desired for food packaging.This study describes a simple technique for the development of advanced multifunctional and fully biodegradable food packaging film and it is a sustainable alternative to plastic packaging.

Smart Colorimetric Corn Starch Films Combined with Anthocyanin-Loaded Glutenin-Carboxymethyl Chitosan Nanocomplexes for Freshness Monitoring of Chilled Pork

In this study,intelligent,pH-responsive colorimetric films were prepared by encapsulating anthocyanins in nanocomplexes prepared from glutenin and carboxymethyl chitosan.These nanocomplexes were added to a corn starch matrix and used in the freshness monitoring of chilled pork.The effects of anthocyanin-loaded nanocomplexes on the physical,structural,and functional characteristics of the films were investigated.The addition of anthocyanin-loaded nanocomplexes increased the tensile strength,elongation at break,hydrophobicity,and light transmittance of the films while decreasing their water vapor permeability.This is because new hydrogen bonds are formed between the film components,resulting in a more homogeneous and dense structure.The colorimetric film has a significant color response to pH changes.These films were used in experiments on the freshness of chilled pork,in which the pH changes with changing freshness states.The results show that the colorimetric film can monitor changes in the freshness of chilled pork in real time,where orange,pink,and green represent the fresh,secondary fresh,and putrefied states of pork,respectively.Therefore,the intelligent colorimetric film developed in this study has good application potential in the food industry.

Adding chitosan nanoparticles of green tea extract in diluent and thawing temperatures ameliorate the post-thawed quality of Boer buck semen

Objective:To improve the quality of post-thawing Boer buck semen for artificial insemination by adding green tea extract chitosan nanoparticles to skimmed egg yolk diluent,and the proper thawing temperature.Methods:The ejaculate of Boer buck was added to skimmed egg yolk diluent without(the control group)and with adding 1μg of chitosan nanoparticles of green tea extract per mL of diluent(the treatment group).Then,the diluted semen was filled in French mini straws containing 60×106 live sperm per straw,frozen in a standard protocol,and stored as frozen semen at−196℃for a week.Six replicates from each group were diluted for 30 s at 37℃or 39℃sterile water to evaluate the semen quality.Results:Post-thawing(at 37℃or 39℃)of live sperm,progressive motility,and plasma membrane integrity were lower compared to those of the pre-freezing stage(P<0.05).Thawing at 37℃resulted in no significant difference in live sperm,progressive motility,and plasma membrane between the control group and the treatment group(P>0.05).The live sperm,progressive motility,and plasma membrane of the treatment group in the pre-freezing stage,and post-thawed at 39℃were higher compared to those of the control group(P<0.05).There was no significant difference in malondialdehyde(MDA)concentration,DNA fragmentation,and catalase concentration of thawing at 37℃compared to those of 39℃in the same group.The MDA concentration and DNA fragmentation in thawing at 37℃and 39℃of the treatment group were significantly lower than those of the control group(P<0.05).However,the catalase concentration in thawing at 37℃and 39℃of the treatment group was not significantly different than the control group(P>0.05).Conclusions:Higher quality post-thawing Boer buck semen is achieved by adding 1μg/mL of chitosan nanoparticles of green tea extract to the skimmed egg yolk diluent and thawing at 39℃.

Extraction, Production and Quality Evaluation of Margarine from Oil Extracted from Waste Biomass Peels of Avocado and Virgin Coconut Oil, Using Chitosan from Reared Shells as Preservative

The production and consumption of avocado pears generates tons of wastes, mainly the pear peels which are usually discarded, although they have been reported to contain important phyto-chemicals with biological activities. The adverse health effect associated with the consumption of saturated lipid based foods has ignited research on reformulation of lipid based foods to eliminate Trans Fatty Acids (TFAs). This study was thus aimed at the extraction and characterization of oil from Avocado Peels (APO) and evaluation of the quality of margarine produced from it. Five verities of pear were used for oil extraction by soxhlet method and physiochemical, oxidative, functional and antioxidant characterization was done. Margarines were formulated using a central composite design using oil blends of APO and Virgin Coconut Oil (VCO) with an oil ratio of 10:90, 40:60, 70:30 respectively, varied blending speed, blending time, and chitosan concentration. Samples were characterized and the effect of process parameters on the physiochemical and functional properties of the margarine studied. Optimized conditions were used to produce samples for sensory evaluation. Color, spreadability, aroma, taste and general acceptability was evaluated using ranking difference test. The results showed that the yield, density, and iodine values of APOs oils ranged from 14.91 ± 0.18 to 11.76 ± 0.46;0.93 ± 0.001 to 0.99 ± 0.1;46.63 ± 1.70 to 52.4 ± 0.63, their acid values, TBA and PV values ranged from 1.42 ± 0.39 to 1.97 ± 0.5;0.11 ± 0.002 to 0.18 ± 0.04;and 2.72 ± 0.14 to 4.43 ± 0.36 respectively, with Brogdon avocado peel variety having the overall best properties prepared blends of trans-free APO margarines showed that increase in APO ratio decreased melting point, increased oxidative stability and reduced moisture content of margarine samples. Chitosan addition leads to decrease moisture content and increase functional properties. VCO lead to increase in phenolic and flavonoid content of the margarines. Samples were spreadable and palatable with R20 being most palatable and the most accepted being R26 with a mean score of 7.07 ± 0.70. Decrease in color intensity increased acceptability. This study therefore demonstrated that avocado peel waste biomass can be valorized by using it as raw material for oil extraction, which can serve as good material for the production of trans-free margarines with good oxidative stability, functional and antioxidant properties.

Nano-Chitosan Loaded N Application for Improving Wheat Plants Yield: Impacts on Soil Nutrient Availability

This work was held to study the effect of chitosan nanoparticles and loaded N on the wheat plants. A field study was conducted during the winter season 2021/2022 cultivated with wheat (Triticum aestivum L.) on sandy soil at the experimental unit of the Faculty of Agriculture farm-Suez Canal University-Ismailia-Egypt. Results may indicate that the application of foliar chitosan NPs.-loaded nitrogen in different concentrations has been employed to enhance plant growth and productivity, Nano-chitosan loaded with N (500 mg/L) yielded the most grains and was more effective than the control and nano-chitosan loaded N (250 mg/L, 750 mg/L).

ZnO Incorporated Acrylamide Grafted Chitosan Based Composite Film for Advanced Wound Healing Applications

This study was carried out to prepare ZnO nanoparticles incorporated acrylamide grafted chitosan composite film for possible biomedical application especially drug loading in wound healing. ZnO nanoparticles were prepared by co-precipitation method from zinc acetate di-hydrate and incorporated in acrylamide grafted chitosan. FT-IR and TGA of the prepared composite film confirmed the successful incorporation of ZnO nanoparticles in the acrylamide-grafted polymer matrix. SEM images showed that the ZnO nanoparticles were homogeneously distributed on the porous matrix of the composite film. Water uptake and buffer uptake analysis revealed that the composite film could hold water and buffer sufficiently, which facilitated the absorption of exudate from the wound site. Amoxicillin was loaded in the prepared composite film and the maximum loading efficiency was found to be 67.33% with drug concentration of 300 ppm. In vitro studies showed greater antimicrobial activity of drug-loaded composite film compared to both pure film and standard antibiotic disc. Finally, the In vivo mouse model showed maximum healing efficiency compared to conventional gauge bandages because the loading of antibiotic in the film produced a synergistic effect and healing time was reduced.

壳聚糖/甘油磷酸钠/海藻酸钠/益母草碱水凝胶的抗炎与促成骨作用

背景:益母草碱具有改善微循环、抗氧化、抗细胞凋亡、清除自由基、抗炎、抗纤维化等多种生物活性作用,并且可促进骨髓间充质干细胞的成骨分化,具有应用于牙周炎治疗的潜能。目的:探讨益母草碱负载于壳聚糖/甘油磷酸钠/海藻酸钠水凝胶的抗炎与促成骨作用。方法:①分别制备壳聚糖/甘油磷酸钠/海藻酸钠水凝胶(空白水凝胶)与壳聚糖/甘油磷酸钠/海藻酸钠/益母草碱水凝胶(载药水凝胶),将两种水凝胶分别培养RAW 264.7细胞、MC3T3-E1细胞,利用CCK-8实验与活/死细胞染色检测水凝胶的细胞毒性。②将RAW 264.7细胞分5组培养:空白组常规培养24 h,脂多糖组加入脂多糖,单独水凝胶组加入脂多糖与空白水凝胶,载药水凝胶组加入脂多糖与载药水凝胶,抑制剂组加入脂多糖、载药水凝胶与PI3K抑制剂LY294002,处理24 h后,利用qRT-PCR法检测炎症相关因子mRNA表达,Western Blotting检测炎症相关因子与PI3K/AKT信号通路的蛋白表达。③将MC3T3-E1细胞分4组培养:空白组不加入任何材料,单独水凝胶组加入空白水凝胶,载药水凝胶组加入载药水凝胶,抑制剂组加入载药水凝胶与PI3K抑制剂LY294002,处理7 d后,进行碱性磷酸酶染色,利用qRT-PCR检测成骨相关因子mRNA表达水平,Western Blotting检测PI3K/AKT信号通路的蛋白表达。结果与结论:①CCK-8实验与活/死细胞染色结果显示,两种水凝胶无细胞毒性作用,具有良好的细胞相容性;②与空白组相比,脂多糖组白细胞介素6、肿瘤坏死因子α、白细胞介素1β的mRNA与蛋白表达升高(P<0.05),p-AKT、p-PI3K、p-p65、p-IκBα的蛋白表达升高(P<0.05);与脂多糖组比较,载药水凝胶组上述指标的mRNA与蛋白表达均降低(P<0.05);与载药水凝胶组相比,抑制剂组上述指标的mRNA与蛋白表达均降低(P<0.05);③载药水凝胶组碱性磷酸酶活性高于空白组、单独水凝胶组、抑制剂组(P<0.05);与空白组相比,单独水凝胶组碱性磷酸酶、Runx2、骨钙素与Ⅰ型胶原的mRNA表达升高(P<0.05),p-AKT、p-PI3K的蛋白表达升高(P<0.05);与单独水凝胶组相比,载药水凝胶组上述指标的mRNA与蛋白表达均升高(P<0.05);与载药水凝胶组相比,抑制剂组上述指标的mRNA与蛋白表达均降低(P<0.05);④结果表明,壳聚糖/甘油磷酸钠/海藻酸钠/益母草碱水凝胶具有抗炎与促成骨作用,该作用可能与调控PI3K/AKT信号通路相关。

Adsorption of Cr(VI) by modified chitosan from heavy-metal polluted water of Xiangjiang River, China

Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate reparative adsorption for Cr（VI） from the polluted Xiangjiang River water. A comparative X-ray analysis shows that the degree of crystallization in the imprinted polymer was significantly weakened, the area of the non-crystalline region was larger. There were more adsorption sites in the imprinted polymer, and the adsorption capacity towards Cr（VI） was increased. The adsorption capacity of the imprinted polymer towards Cr（VI） increased with time and reaches saturation after 8 h. The optimal adsorption time was 4-8 h after the adsorption starting and the optimal pH value for the solution was in the range of 4.5-7.5. When the chitosan reaches saturation, the adsorption capacity achieves a state of equilibrium, and the maximum Cr（VI） extraction rate reaches 33.7%. Moreover, the adsorption capacity of the imprinted polymer towards Cr（VI） increases with increasing chitosan concentration. In this situation, the Cr（VI） extraction rate shows little variation, and the maximum removal rate can reach 98.3%. Furthermore, the Cr（VI） extraction rate increases with an increase in the degree of deacetylation in the chatoyant and chitosan, with the best adsorption effect corresponding to 90% deacetylation. Fitting the adsorption data to the quasi first- and second-order kinetic models yields correlation coefficients of 0.9013 and 0.9875, respectively. The corresponding rate constants for the two models are 0.0091 min-1 and 7.129 g/（mg.min）, respectively. Hence, the adsorption using Cr（VI）-imprinted chitosan is more consistent with the second-order kinetics. Comparing the data to Freundlich and Langrnuir adsorption isotherms shows that the latter has a better linear fit and a maximum adsorption capacity of 15.784 mg/g.

Chitosan-DNA介导关节基因转移的体外研究

目的 :探索体外Chitosan对关节软骨细胞、滑膜细胞的转染。方法 :分离培养兔正常滑膜细胞、软骨细胞 ,使用荧光质粒 pEGFP -C3作为报道基因 ,制备Chitosan -DNA超微颗粒转染兔正常软骨细胞、滑膜细胞 ,荧光显微镜观察绿色荧光蛋白的表达。结果 :Chitosan能将DNA带入胞内 ,该DNA超微颗粒随时间的延长可缓慢进入胞内 ,其包被的DNA也可以被缓慢释放 ,且对软骨细胞的转染能力强。结论 :Chitosan在体外可介导关节软骨细胞、滑膜细胞基因转移 ,为今后关节疾病非病毒基因转移的研究提供实验依据。

Antoioxidant Activity of Carboxymethyl Chitosan with Different Substituted Degrees

[Objective] In order to study the relations among different positions, degrees of substitution and antioxidant ability. [Method] N, O-carboxymethyl chitosan （NOA, NOB and NOC）with various degrees of substitution （DS）were obtained by etherizing chito-oligosacchaside. Their structure and substituted degree were characterized and their antioxldant activity to·OH was evaluated. [ Result] The IC50 s of NOA ,NOB and NOC were 0.15 ,0. 29 ,0. 23 mg/ml while their DSs of -NH2 position（DSN） were 0.51,0.29 and 0.38 and DSo were 0. 74 ,0. 84 ,0. 97respectively.[ Conclusion] With the increase of DSN ,antioxidant activity of N,O-carboxymethyl chitosan oligosaccharide to·OH was up.

Effects of Chitosan and Salicylic Acid on Cold Resistance of Litchi under Low Temperature

This paper focused on the effect of spraying chitosan and salicylic acid to Litchi under low temperature stress conditions.The physiology and biochemistry of litchi were studied as well.Results showed that the appropriate concentration of chitosan and salicylic acid treatment could effectively reduce injury caused by low temperature to litchi,compared with water control,chlorophyll,proline,soluble protein content of litchi after treatment and the activity of protective enzyme increasing significantly.However,the accumulation of resistance could significantly be improved.Furthermore,when 1 000 mg/L chitosan combined with 50 mg/L salicylic acid,the litchi acquired the best cold resistance capability.

壳聚糖-绿原酸复合保鲜剂对冷藏鮰鱼片食用品质的影响

采用无菌水(CK组)、3.0 mg/mL绿原酸(chlorogenic acid,CGA)溶液(CGA组)、1.0 mg/mL壳聚糖(chitosan,CTS)溶液(CTS组)、1.0 mg/mL CTS和3.0 mg/mL CGA混合溶液(C+组)浸泡鮰鱼片后低温贮藏,通过对比不同贮藏时间鮰鱼片蒸煮损失率及熟制后鱼肉剪切力、微观结构、水分分布、挥发性成分等指标的变化情况,分析CTS-CGA复合保鲜剂对冷藏鮰鱼片食用品质的影响。结果表明:随着贮藏时间的延长,鮰鱼片蒸煮损失率上升,熟制后剪切力下降、肌肉纤维由有序变为无序,鱼肉中水分流动性和相对含量逐渐下降。贮藏6 d后,CK组不良风味物质相对含量显著高于C+组;其中,CK组己醛和三甲胺相对含量分别为40.11%和8.87%;C+组己醛相对含量仅为5.33%,未检出三甲胺,CTS-CGA复合保鲜剂可有效抑制不良风味的产生。综上,CTS-CGA复合保鲜剂可有效延缓鮰鱼片质地劣变,延缓鮰鱼片食用品质下降。