Currently,most two-dimensional(2D)materials that are of interest to emergent applications have focused on van der Waals–layered materials(VLMs)because of the ease with which the layers can be separated(e.g.,graphene)...Currently,most two-dimensional(2D)materials that are of interest to emergent applications have focused on van der Waals–layered materials(VLMs)because of the ease with which the layers can be separated(e.g.,graphene).Strong interlayer-bonding-layered materials(SLMs)in general have not been thoroughly explored,and one of the most critical present issues is the huge challenge of their preparation,although their physicochemical proper-ty transformation should be richer than VLMs and deserves greater attention.MAX phases are a classi-cal kind of SLM.展开更多
A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubula...A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.展开更多
背景:石墨烯是最薄、最强韧的一类二维新型晶体材料,在生物医学的应用中显示出巨大的优势。血管生成和血管化骨是组织修复和再生的关键,是解决血管和成骨问题的有效途径。目的:综述石墨烯及其衍生物促进血管生成和血管化骨的特性及机制...背景:石墨烯是最薄、最强韧的一类二维新型晶体材料,在生物医学的应用中显示出巨大的优势。血管生成和血管化骨是组织修复和再生的关键,是解决血管和成骨问题的有效途径。目的:综述石墨烯及其衍生物促进血管生成和血管化骨的特性及机制,为其在血管化组织修复与再生的临床应用提供参考。方法:利用计算机检索PubMed、ScienceDirect、中国知网和万方数据库收录的相关文献,中文检索词为“石墨烯,血管生成,血管化,血管化骨,内皮细胞”,英文检索词为“graphene,Angiogenesis OR Vascularization,Vascularized bone,endothelial cells”。排除与文章主题不相关的文献,根据纳入标准和排除标准,最终纳入62篇文献进行结果分析。结果与结论:①目前氧化石墨烯在石墨烯及其衍生物中的研究较多,应用最为广泛。②石墨烯及其衍生物适用于心脏、骨、神经和创伤愈合等相关疾病。③石墨烯及其衍生物有优异的理化性能和生物学性能,但其存在潜在的细胞毒性,在应用中需注意其生物安全性。④石墨烯及其衍生物的应用还需要进一步的研究来证明其最适尺寸和浓度及降低毒性的措施。⑤就细胞层面而言,石墨烯及其衍生物可以通过促进尖端内皮细胞表型、间充质干细胞黏附和增殖、血管平滑肌细胞的生长,从而促进血管生成活性。⑥就分子层面而言,石墨烯及其衍生物可以增加血管内皮生长因子、碱性成纤维细胞生长因子及肝细胞生长因子等的表达并活化活性氧/一氧化氮合酶/一氧化氮信号通路、溶血磷脂酸R6/Hippo-YAP通路、基质细胞衍生因子1/血管内皮生长因子和ZEB1/Notch1通路。⑦氧化石墨烯和氧化石墨烯-铜可以磷酸化细胞外调节蛋白激酶并激活缺氧诱导因子1,进而促进血管内皮生长因子和骨形态生成蛋白2的表达上调,从而促进血管生成和血管化骨。⑧因此,石墨烯及其衍生物特别是氧化石墨烯由于具有优良的生物学性能、良好的促血管生成及促血管化骨能力,在血管化组织修复与再生方面有很大的应用前景。展开更多
Establishing an appropriate degradation rate is critical for tissue engineering scaffolds. In this study, the degradation rate of silk fibroin three-dimensional scaffolds was regulated by changing the molecular weight...Establishing an appropriate degradation rate is critical for tissue engineering scaffolds. In this study, the degradation rate of silk fibroin three-dimensional scaffolds was regulated by changing the molecular weight (MW) of the silk fibroin. The solubility of silk fibroin depends primarily on the ionic ability of the slovent to dissolve silk fibroin, therefore, we regulated the MW of the silk fibroin using LiBr, Ca(NO3)2 and CaCl2 to dissolve the silk fibers. SDS-PAGE analysis showed that the MW of the CaCl2-derived silk fibroin was lower than the MW produced using LiBr and Ca(NO3)2. In vitro and in vivo degradation results showed that the scaffolds prepared by low-MW silk fibroin were more rapidly degraded. Furthermore, FTIR and amino acid analysis suggested that the amorphous regions were preferentially degraded by Collagenase IA, while the SDS-PAGE and amino acid analysis indicated that the scaffolds were degraded into polypeptides (mainly at 10-30 kDa) and amino acids. Because the CaCl2-derived scaffolds contained abundant low MW polypeptides, inter-intramolecular entanglement and traversing of molecular chains in the crystallites reduced, which resulted in rapid degradation. The in vivo degradation results suggested that the degradation rate of the CaCl2-derived scaffolds was better matched to dermis regeneration, indicating that the degradation rate of silk fibroin can be effectively regulated by changing the MW to achieve a suitable dermal tissue regeneration rate.展开更多
基金This research was supported by the National Natural Science Foundation of China(21673161 and 21473124)the Sino-German Center for Research Promotion(1400)STEM characterization was conducted at the Center for Nanophase Materials Sciences,which is a DOE Office of Science User Facility.Work at Jilin University is supported by the Recruitment Program of Global Youth Experts in China and National Natural Science Founda-tion of China(11404131 and 11674121).
文摘Currently,most two-dimensional(2D)materials that are of interest to emergent applications have focused on van der Waals–layered materials(VLMs)because of the ease with which the layers can be separated(e.g.,graphene).Strong interlayer-bonding-layered materials(SLMs)in general have not been thoroughly explored,and one of the most critical present issues is the huge challenge of their preparation,although their physicochemical proper-ty transformation should be richer than VLMs and deserves greater attention.MAX phases are a classi-cal kind of SLM.
基金Fundamental Research Funds for the Central UniversitiesNational Natural Science Foundation of China(No.31100682)
文摘A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.
文摘背景:石墨烯是最薄、最强韧的一类二维新型晶体材料,在生物医学的应用中显示出巨大的优势。血管生成和血管化骨是组织修复和再生的关键,是解决血管和成骨问题的有效途径。目的:综述石墨烯及其衍生物促进血管生成和血管化骨的特性及机制,为其在血管化组织修复与再生的临床应用提供参考。方法:利用计算机检索PubMed、ScienceDirect、中国知网和万方数据库收录的相关文献,中文检索词为“石墨烯,血管生成,血管化,血管化骨,内皮细胞”,英文检索词为“graphene,Angiogenesis OR Vascularization,Vascularized bone,endothelial cells”。排除与文章主题不相关的文献,根据纳入标准和排除标准,最终纳入62篇文献进行结果分析。结果与结论:①目前氧化石墨烯在石墨烯及其衍生物中的研究较多,应用最为广泛。②石墨烯及其衍生物适用于心脏、骨、神经和创伤愈合等相关疾病。③石墨烯及其衍生物有优异的理化性能和生物学性能,但其存在潜在的细胞毒性,在应用中需注意其生物安全性。④石墨烯及其衍生物的应用还需要进一步的研究来证明其最适尺寸和浓度及降低毒性的措施。⑤就细胞层面而言,石墨烯及其衍生物可以通过促进尖端内皮细胞表型、间充质干细胞黏附和增殖、血管平滑肌细胞的生长,从而促进血管生成活性。⑥就分子层面而言,石墨烯及其衍生物可以增加血管内皮生长因子、碱性成纤维细胞生长因子及肝细胞生长因子等的表达并活化活性氧/一氧化氮合酶/一氧化氮信号通路、溶血磷脂酸R6/Hippo-YAP通路、基质细胞衍生因子1/血管内皮生长因子和ZEB1/Notch1通路。⑦氧化石墨烯和氧化石墨烯-铜可以磷酸化细胞外调节蛋白激酶并激活缺氧诱导因子1,进而促进血管内皮生长因子和骨形态生成蛋白2的表达上调,从而促进血管生成和血管化骨。⑧因此,石墨烯及其衍生物特别是氧化石墨烯由于具有优良的生物学性能、良好的促血管生成及促血管化骨能力,在血管化组织修复与再生方面有很大的应用前景。
文摘Establishing an appropriate degradation rate is critical for tissue engineering scaffolds. In this study, the degradation rate of silk fibroin three-dimensional scaffolds was regulated by changing the molecular weight (MW) of the silk fibroin. The solubility of silk fibroin depends primarily on the ionic ability of the slovent to dissolve silk fibroin, therefore, we regulated the MW of the silk fibroin using LiBr, Ca(NO3)2 and CaCl2 to dissolve the silk fibers. SDS-PAGE analysis showed that the MW of the CaCl2-derived silk fibroin was lower than the MW produced using LiBr and Ca(NO3)2. In vitro and in vivo degradation results showed that the scaffolds prepared by low-MW silk fibroin were more rapidly degraded. Furthermore, FTIR and amino acid analysis suggested that the amorphous regions were preferentially degraded by Collagenase IA, while the SDS-PAGE and amino acid analysis indicated that the scaffolds were degraded into polypeptides (mainly at 10-30 kDa) and amino acids. Because the CaCl2-derived scaffolds contained abundant low MW polypeptides, inter-intramolecular entanglement and traversing of molecular chains in the crystallites reduced, which resulted in rapid degradation. The in vivo degradation results suggested that the degradation rate of the CaCl2-derived scaffolds was better matched to dermis regeneration, indicating that the degradation rate of silk fibroin can be effectively regulated by changing the MW to achieve a suitable dermal tissue regeneration rate.
