Because of the incomparable merits （nontoxicity, non-remainder, fast transfer mass） of supercritical carbon dioxide fluid technique（SC-CO2）, it was used to developed a series of novel biodegradable tissue engineer...Because of the incomparable merits （nontoxicity, non-remainder, fast transfer mass） of supercritical carbon dioxide fluid technique（SC-CO2）, it was used to developed a series of novel biodegradable tissue engineering scaffold materials in this research. The novel PLA/chitosan composite materials could be molded to different shapes, and the porosity of the materials were over 200 lam and connected. Chondrocyte cultivation, subcutaneous and intramuscular implantation were mainly discussed this paper. The results showed that the cells could well adhere, grow and multiplicate on the surface of the materials, which indicated good biocompatibility of the composite materials. The plantation test revealed that the PLA materials had already dismissed 2 month late in the body, while the composite materials could still keep certain strength and shape, and the most important things is the response of the tissue toward the implanted PLA/chitosan composite materials was mild and had far less inflammation than PLA materials. 8 to 16 weeks later, fiber membrane was stable; degradation of the materials was seen clear and tissue had already spread into it.展开更多
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 bioactiv...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.展开更多
This work aims to prepare chitosan(CS)-based coated layers,CS(10 wt%nanosilver/90 wt%CS,10 wt%biotin/90 wt%CS,and 5 wt%nanosilver–5 wt%biotin)/90 wt%CS coatings are prepared,onto pure Ti substrate.The surface morphol...This work aims to prepare chitosan(CS)-based coated layers,CS(10 wt%nanosilver/90 wt%CS,10 wt%biotin/90 wt%CS,and 5 wt%nanosilver–5 wt%biotin)/90 wt%CS coatings are prepared,onto pure Ti substrate.The surface morphology of the novel CS composite coating was studied using field emission scanning electron microscopy,atomic force microscopy(AFM),Fourier transforms infrared(FTIR)and wettability test.Results show that the addition of(biotin,nanosilver)5 Vol.%improves the properties of composite materials.Using different particles’scale size aid in improving the combinations in the alginate,producing a dual effect on film properties.Coating surface roughness decreased in the chitosan-based biocomposite with preferable homogeneity and crack-free coating layers,as confirmed by AFM.An increase in surface roughness ensured substitution,which enhanced the surface structures.The high wettability of the CS-based coating layers was due to the presence of nanoparticles,and the composite coatings with CS,nanosilver,or biotin had excellent wettability because of the good hydrophilic nature of the CS matrix combined with reinforced particles.The FTIR results showed that peaks of the blending of CS plus nanoparticles,CS plus biotin,or CS plus nanosilver plus biotin were excellent matching with no changes in the structure of the matrix.展开更多
The increasing demand for sustainable and environmentally friendly materials has driven research towards the development of green composites.In this work,the flax/polylactic acid(PLA)braided yarns were fabricated by b...The increasing demand for sustainable and environmentally friendly materials has driven research towards the development of green composites.In this work,the flax/polylactic acid(PLA)braided yarns were fabricated by braiding PLA filaments with 4 to 24 spindles on flax yarns.After curing at different temperatures(180℃and 190℃),the core/sheath structural flax/PLA composite yarns were manufactured.According to the results of the tensile test,the flax/PLA composite yarn with 4-spindle PLA yarns as a sheath layer and at a curing temperature of 180℃reached the maximum elastic modulus of about(5.79±0.65)GPa and the maximum tensile strength of about(162.17±18.18)MPa.This flax/PLA composite yarn with good mechanical properties would be suitable for green composites in the automobile manufacturing industry and building materials.展开更多
Biodegradable polylactic acid(PLA)melt-blown nonwovens are attractive candidates to replace nondegradable polypropylene melt-blown nonwovens.However,it is still an extremely challenging task to prepare PLA melt-blown ...Biodegradable polylactic acid(PLA)melt-blown nonwovens are attractive candidates to replace nondegradable polypropylene melt-blown nonwovens.However,it is still an extremely challenging task to prepare PLA melt-blown nonwovens with sufficient mechanical properties for practical application.Herein,we report a simple strategy for the large-scale preparation of biodegradable PLA/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)melt-blown nonwovens with high strength and excellent toughness.In this process,a small amount of PHBV is added to PLA to improve the latter’s crystallization rate and crystallinity.In addition,when the PHBV content increases from 0 to 7.5 wt%,the diameters of the PLA/PHBV melt-blown fibers decrease significantly(with the proportion of nanofibers increasing from 7.7%to 42.9%).The resultant PLA/PHBV(5 wt%PHBV)melt-blown nonwovens exhibit the highest mechanical properties.The tensile stress,elongation,and toughness of PLA/PHBV(5 wt%PHBV)melt-blown nonwovens reach 2.5 MPa,45%,and 1.0 MJm3,respectively.More importantly,PLA/PHBV melt-blown nonwovens can be completely degraded into carbon dioxide and water after four months in the soil,making them environmentally friendly.A general tensile-failure model of melt-blown nonwovens is proposed in this study,which may shed light on mechanical performance enhancement for nonwovens.展开更多
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 trac...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.展开更多
基金This work was supported by the national key project“973”program of China.(No.G1999054306)“863”program of ministry of education in China(2OOlAA625050)Guangdong Science and technology bureau(No.A302020104).
文摘Because of the incomparable merits （nontoxicity, non-remainder, fast transfer mass） of supercritical carbon dioxide fluid technique（SC-CO2）, it was used to developed a series of novel biodegradable tissue engineering scaffold materials in this research. The novel PLA/chitosan composite materials could be molded to different shapes, and the porosity of the materials were over 200 lam and connected. Chondrocyte cultivation, subcutaneous and intramuscular implantation were mainly discussed this paper. The results showed that the cells could well adhere, grow and multiplicate on the surface of the materials, which indicated good biocompatibility of the composite materials. The plantation test revealed that the PLA materials had already dismissed 2 month late in the body, while the composite materials could still keep certain strength and shape, and the most important things is the response of the tissue toward the implanted PLA/chitosan composite materials was mild and had far less inflammation than PLA materials. 8 to 16 weeks later, fiber membrane was stable; degradation of the materials was seen clear and tissue had already spread into it.
基金supported by the National Natural Science Foundation of China (52373091,52173084,51973192,51603122)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering (2021SZ-FR002)。
基金supported by the National Natural Science Foundation of China,Nos.81941011(to XL),31771053(to HD),31730030(to XL),31971279(to ZY),31900749(to PH),31650001(to XL),31320103903(to XL),31670988(to ZY)the Natural Science Foundation of Beijing,Nos.7222004(to HD)+1 种基金a grant from Ministry of Science and Technology of China,Nos.2017YFC1104002(to ZY),2017YFC1104001(to XL)a grant from Beihang University,No.JKF-YG-22-B001(to FH)。
文摘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.
文摘This work aims to prepare chitosan(CS)-based coated layers,CS(10 wt%nanosilver/90 wt%CS,10 wt%biotin/90 wt%CS,and 5 wt%nanosilver–5 wt%biotin)/90 wt%CS coatings are prepared,onto pure Ti substrate.The surface morphology of the novel CS composite coating was studied using field emission scanning electron microscopy,atomic force microscopy(AFM),Fourier transforms infrared(FTIR)and wettability test.Results show that the addition of(biotin,nanosilver)5 Vol.%improves the properties of composite materials.Using different particles’scale size aid in improving the combinations in the alginate,producing a dual effect on film properties.Coating surface roughness decreased in the chitosan-based biocomposite with preferable homogeneity and crack-free coating layers,as confirmed by AFM.An increase in surface roughness ensured substitution,which enhanced the surface structures.The high wettability of the CS-based coating layers was due to the presence of nanoparticles,and the composite coatings with CS,nanosilver,or biotin had excellent wettability because of the good hydrophilic nature of the CS matrix combined with reinforced particles.The FTIR results showed that peaks of the blending of CS plus nanoparticles,CS plus biotin,or CS plus nanosilver plus biotin were excellent matching with no changes in the structure of the matrix.
基金National Natural Science Foundation of China(No.52273054)Shanghai Natural Science Foundation,China(No.20ZR1402200)。
文摘The increasing demand for sustainable and environmentally friendly materials has driven research towards the development of green composites.In this work,the flax/polylactic acid(PLA)braided yarns were fabricated by braiding PLA filaments with 4 to 24 spindles on flax yarns.After curing at different temperatures(180℃and 190℃),the core/sheath structural flax/PLA composite yarns were manufactured.According to the results of the tensile test,the flax/PLA composite yarn with 4-spindle PLA yarns as a sheath layer and at a curing temperature of 180℃reached the maximum elastic modulus of about(5.79±0.65)GPa and the maximum tensile strength of about(162.17±18.18)MPa.This flax/PLA composite yarn with good mechanical properties would be suitable for green composites in the automobile manufacturing industry and building materials.
基金supported by the National Key Research and Development Program of China(2022YFB3804903 and 2022YFB3804900)the National Natural Science Foundation of China(52273052)+1 种基金the Program of Shanghai Academic/Technology Research Leader(21XD1420100)the International Cooperation Fund of Science and Technology Commission of Shanghai Municipality(21130750100).
文摘Biodegradable polylactic acid(PLA)melt-blown nonwovens are attractive candidates to replace nondegradable polypropylene melt-blown nonwovens.However,it is still an extremely challenging task to prepare PLA melt-blown nonwovens with sufficient mechanical properties for practical application.Herein,we report a simple strategy for the large-scale preparation of biodegradable PLA/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)melt-blown nonwovens with high strength and excellent toughness.In this process,a small amount of PHBV is added to PLA to improve the latter’s crystallization rate and crystallinity.In addition,when the PHBV content increases from 0 to 7.5 wt%,the diameters of the PLA/PHBV melt-blown fibers decrease significantly(with the proportion of nanofibers increasing from 7.7%to 42.9%).The resultant PLA/PHBV(5 wt%PHBV)melt-blown nonwovens exhibit the highest mechanical properties.The tensile stress,elongation,and toughness of PLA/PHBV(5 wt%PHBV)melt-blown nonwovens reach 2.5 MPa,45%,and 1.0 MJm3,respectively.More importantly,PLA/PHBV melt-blown nonwovens can be completely degraded into carbon dioxide and water after four months in the soil,making them environmentally friendly.A general tensile-failure model of melt-blown nonwovens is proposed in this study,which may shed light on mechanical performance enhancement for nonwovens.
基金supported by Localization of oxygen radicals and enzymes in bivalve haemocytes to Jing Liu(20230058,6602423063).
文摘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.
