This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Esche...This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus,were conducted.Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone(PCL).Inhibition rates of polycaprolactone/quaternized chitosan were 39.2%99.9%against Escherichia coli,while inhibition rate was 40.9%99.9%against Staphylococcus aureus.When quaternized chitosan(QCTS)content was up to 20%,blends exhibited 99.9%inhibition rates against both two types of bacteria.展开更多
Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivat...Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.展开更多
Hydroxypropyltrimethyl ammonium chloride chitosan(HACC)and hydroxypropyltrimethyl ammonium chloride fully deacetylated chitosan(De-HACC)were synthesized with various degrees of substitution by altering the ratio of ch...Hydroxypropyltrimethyl ammonium chloride chitosan(HACC)and hydroxypropyltrimethyl ammonium chloride fully deacetylated chitosan(De-HACC)were synthesized with various degrees of substitution by altering the ratio of chitosan to glycidyl trimethyl-ammonium chloride(GTMAC).The effects of the quaternary ammonium degree and the acetyl group of these polymers on immunostimulatory activities were detected in RAW 264.7 cells.The expression levels of nitrogen oxide(NO),interleukin-6(IL-6)and tumor necrosis factor(TNF-α)were compared.Results show that the removal of acetyl groups in chitosan obviously improved the degree of substitution of quaternary ammonium salts.In addition,HACC and De-HACC were capable of promoting immunological activity in a substitution-dependent manner;HACC was positively correlated,and De-HACC was negatively correlated.Among tested ratios,HACC-30%and De-HACC-54%performed better than the others,and De-HACC-54%performed the best.Generally,quaternized chitosan possesses immunostimulatory activity,which is related to the degree of quaternization and the acetyl group.展开更多
A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-...A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, (HNMR)-H-1 and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.展开更多
Cellulose nanofibers(CNF)are considered to be a potential substrate of energy material for energy storage devices due to the foldable,lightweight,recyclable and environmentally friendly feature.However,the energy mate...Cellulose nanofibers(CNF)are considered to be a potential substrate of energy material for energy storage devices due to the foldable,lightweight,recyclable and environmentally friendly feature.However,the energy materials tend to distribute unevenly or fall off from CNF easily,resulting in the decrease of the devices’overall performance.Here,for the first time,we used quaternized chitosan(QCS)as stabilizer and adhesive to in situ synthesize and deposite copper sulfide nanocrystals(CuS-NCs)on CNF and further obtained the conductive paper for flexible supercapacitors.In the presence of QCS,CuS-NCs deposited in situ on CNF can be capped and stabilized by the QCS molecular chains for uniform distribution,which is conducive to the capacitive behavior and electrochemical stability of composite paper.The result shows that the specific capacitance of the composite paper was as high as 314.3 F/g at a current density of 1 A/g,a high rate capacitance of 252.6 F/g was achieved even at a high current density of 10 A/g.It reveals that the composite paper exhibited better electrochemical performance than many other CuS-based electrode materials for supercapacitor.More importantly,the composite paper performed well in various folding state without changing much electrochemical performance.Therefore,this work provides a novel strategy to in situ fabricate paper-based electrode for nextgeneration flexible energy-storage system.展开更多
Innovative biomedical applications have high requirements for biomedical materials.Herein,a series of biocompatible,antibacterial and hemostatic sponges were successfully fabricated for the treatment of acute upper ga...Innovative biomedical applications have high requirements for biomedical materials.Herein,a series of biocompatible,antibacterial and hemostatic sponges were successfully fabricated for the treatment of acute upper gastrointestinal bleeding(AUGB).Quaternized chitosan(QC)and soy protein isolate(SPI)were chemically cross-linked to obtain porous SPI/QC sponges(named SQS-n,with n¼30,40,50 or 60 corresponding to the weight percentage of the QC content).The chemical composition,physical properties and biological activity of SQS-n were investigated.SQS-n could support the adhesion and proliferation of L929 cells while triggering no obvious blood toxicity.Meanwhile,SQS-n exhibited good broad-spectrum antibacterial activity against both grampositive bacteria(Staphylococcus aureus)and gram-negative bacteria(Escherichia coli).The in vivo hemostatic effect of SQS-n was evaluated using three different bleeding models.The results revealed that SQS-50 performed best in reducing blood loss and hemostatic time.The overall hemostatic effect of SQS-50 was comparable to that of a commercial gelatin sponge.The enhanced antibacterial and hemostatic activities of SQS-n were mainly attributed to the QC component.In conclusion,this work developed a QC-functionalized hemostatic sponge that is highly desirable for innovative biomedical applications,such as AUGB.展开更多
基金the Science Foundations from Department of Education,Fujian Province,China(JZ180899).
文摘This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus,were conducted.Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone(PCL).Inhibition rates of polycaprolactone/quaternized chitosan were 39.2%99.9%against Escherichia coli,while inhibition rate was 40.9%99.9%against Staphylococcus aureus.When quaternized chitosan(QCTS)content was up to 20%,blends exhibited 99.9%inhibition rates against both two types of bacteria.
基金This project is supported by the Natural Science Foundation of Tianjin （No. 043610611）
文摘Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.
基金*Supported by Key Deployment Projects of the Marine Science Research Center of Chinese Academy of Sciences(No.COMS2020J04)。
文摘Hydroxypropyltrimethyl ammonium chloride chitosan(HACC)and hydroxypropyltrimethyl ammonium chloride fully deacetylated chitosan(De-HACC)were synthesized with various degrees of substitution by altering the ratio of chitosan to glycidyl trimethyl-ammonium chloride(GTMAC).The effects of the quaternary ammonium degree and the acetyl group of these polymers on immunostimulatory activities were detected in RAW 264.7 cells.The expression levels of nitrogen oxide(NO),interleukin-6(IL-6)and tumor necrosis factor(TNF-α)were compared.Results show that the removal of acetyl groups in chitosan obviously improved the degree of substitution of quaternary ammonium salts.In addition,HACC and De-HACC were capable of promoting immunological activity in a substitution-dependent manner;HACC was positively correlated,and De-HACC was negatively correlated.Among tested ratios,HACC-30%and De-HACC-54%performed better than the others,and De-HACC-54%performed the best.Generally,quaternized chitosan possesses immunostimulatory activity,which is related to the degree of quaternization and the acetyl group.
文摘A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, (HNMR)-H-1 and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.
基金This work was financially supported by this work was supported by State Key Laboratory of Pulp and Paper Engineering(No.2020ZR05)the National Natural Science Foundation of China(No.31622044)the project from and the Fundamental Research Funds for the Central Universities(No.2020ZYGXZR066).
文摘Cellulose nanofibers(CNF)are considered to be a potential substrate of energy material for energy storage devices due to the foldable,lightweight,recyclable and environmentally friendly feature.However,the energy materials tend to distribute unevenly or fall off from CNF easily,resulting in the decrease of the devices’overall performance.Here,for the first time,we used quaternized chitosan(QCS)as stabilizer and adhesive to in situ synthesize and deposite copper sulfide nanocrystals(CuS-NCs)on CNF and further obtained the conductive paper for flexible supercapacitors.In the presence of QCS,CuS-NCs deposited in situ on CNF can be capped and stabilized by the QCS molecular chains for uniform distribution,which is conducive to the capacitive behavior and electrochemical stability of composite paper.The result shows that the specific capacitance of the composite paper was as high as 314.3 F/g at a current density of 1 A/g,a high rate capacitance of 252.6 F/g was achieved even at a high current density of 10 A/g.It reveals that the composite paper exhibited better electrochemical performance than many other CuS-based electrode materials for supercapacitor.More importantly,the composite paper performed well in various folding state without changing much electrochemical performance.Therefore,this work provides a novel strategy to in situ fabricate paper-based electrode for nextgeneration flexible energy-storage system.
基金This work was supported by the Medical Science Advancement Program(Clinical Medicine)of Wuhan University(TFLC2018003)the Horizontal Research Program of Zhengzhou University(24110005)+1 种基金the Science and Technology Department of Hubei Province Key Project(2018ACA159)the Chinese Central Special Fund for Local Science and Technology Development of Hubei Province(2018ZYYD023).
文摘Innovative biomedical applications have high requirements for biomedical materials.Herein,a series of biocompatible,antibacterial and hemostatic sponges were successfully fabricated for the treatment of acute upper gastrointestinal bleeding(AUGB).Quaternized chitosan(QC)and soy protein isolate(SPI)were chemically cross-linked to obtain porous SPI/QC sponges(named SQS-n,with n¼30,40,50 or 60 corresponding to the weight percentage of the QC content).The chemical composition,physical properties and biological activity of SQS-n were investigated.SQS-n could support the adhesion and proliferation of L929 cells while triggering no obvious blood toxicity.Meanwhile,SQS-n exhibited good broad-spectrum antibacterial activity against both grampositive bacteria(Staphylococcus aureus)and gram-negative bacteria(Escherichia coli).The in vivo hemostatic effect of SQS-n was evaluated using three different bleeding models.The results revealed that SQS-50 performed best in reducing blood loss and hemostatic time.The overall hemostatic effect of SQS-50 was comparable to that of a commercial gelatin sponge.The enhanced antibacterial and hemostatic activities of SQS-n were mainly attributed to the QC component.In conclusion,this work developed a QC-functionalized hemostatic sponge that is highly desirable for innovative biomedical applications,such as AUGB.
文摘以戊二醛为交联剂,在壳聚糖膜上涂敷壳聚糖季铵盐(HACC),制备了壳聚糖/壳聚糖季铵盐复合膜,并研究了壳聚糖季铵盐的取代度和戊二醛用量对复合膜各种性能的影响.用盐酸环丙沙星作为模型药物进行膜后载药,探讨了复合膜的药物缓释性能.结果表明:随交联剂用量增加复合膜的抗张强度先增后减,当交联剂用量为壳聚糖季铵盐用量的0.2%时,干、湿膜的抗张强度最大;所有复合膜的吸水率和抑菌性均较壳聚糖膜有所提高,且随着取代度增大,膜的吸水率和抑菌性增加;膜的吸水率和抑菌性随着交联剂用量增加而下降.膜的载药量随取代度和交联剂用量的增加而变小,载药膜有较好的药物缓释性能,药物释放可达180 h.
