The synthesis and characterization of PEG-like macromolecular structures on Nit inol surface from tri (ethylene glycol) dimethyl-ether under ECR-cold-plasma conditions were discussed. It was demonstrated that based o...The synthesis and characterization of PEG-like macromolecular structures on Nit inol surface from tri (ethylene glycol) dimethyl-ether under ECR-cold-plasma conditions were discussed. It was demonstrated that based on high-resolution ES CA, ATR-FTIR and contact angle investigations, the deposited PEG-like layers a re composed mainly of -CH 2-CH 2-O- linkages. These structures have a relati vely low contact angle. Compared to the unmodified surfaces, the plasma-treated Nitinol surfaces are more hydrophilic. Plasma enhanced coatings of PEG-like la yers can prevent Ni ion from releasing, thereby improving the biocompatibility o f Nitinol.展开更多
A poly（ethylene glycol） （PEG-like） coating was developed to improve the biocom- patibility of Nickel-Titanium （NiTi） alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a ro...A poly（ethylene glycol） （PEG-like） coating was developed to improve the biocom- patibility of Nickel-Titanium （NiTi） alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a room temperature of 298 K through a ECR （electron-cyclotron resonance） cold-plasma enhanced chemical vapor deposition method using tetraglyme （CH3-O- （CH2-CH2-O）4-CH3） as a precursor. A power supply with a frequency of 2.45 GHz was applied to ignite the plasma with Ar（argon） used as the carrier gas. Based on the atomic force microscopy （AFM） studies, a thin smooth coating on NiTi substrates with highly amorphous functional groups on the modified NiTi surfaces were mainly the same accumulated stoichiometric ratio of C and O with PEG. The vitro studies showed that platelet-rich plasma （PRP） adsorption on the modified NiTi alloy surface was significantly reduced. This study indicated that plasma surface modification changes the surface components of NiTi alloy and subsequently improves its biocompatibility.展开更多
A water soluble hydroxy-capped comb-like poly(ethylene glycol)(CPEG) was prepared via atom transfer radical polymerization(ATRP).A stable CPEG coating was obtained via dip-coating followed by curing at 70℃ for 48 h.T...A water soluble hydroxy-capped comb-like poly(ethylene glycol)(CPEG) was prepared via atom transfer radical polymerization(ATRP).A stable CPEG coating was obtained via dip-coating followed by curing at 70℃ for 48 h.The CPEG-modified surface was proved to be stable in both aqueous environment and ambient according to contact angle behavior and weight decrement testing.The coating forming mechanism was investigated through FTIR,the spectra data demonstrated the stability of CPEG coating derived from its hydrogen bond of inter-molecules and intra-molecules.Platelet experiment showed CPEG modified surface reacted extremely weakly with platelet and showed excellent thrombus resistance than that of both on the pure PET surface and PET surface modified with linear PEG.The model drug RD6G was applied to fabricate a drug-buried CPEG coating surface.The drug-releasing curve demonstrated the stability of the CPEG coating and the controlled-release behavior of RD6G.The unique property of CPEG coating surface provided the potential application in the immobilization and release of aqueous drug,including protein and peptide.展开更多
Tremellafuciformis is one of higher basidiomycetes. Its basidiospore can reproduce yeast-like conidia, which is also called the blastospore by budding. The yeast-like conidia of T. fuciformis is monokaryotic and easy ...Tremellafuciformis is one of higher basidiomycetes. Its basidiospore can reproduce yeast-like conidia, which is also called the blastospore by budding. The yeast-like conidia of T. fuciformis is monokaryotic and easy to culture by submerged fermentation similar to yeast. Thus, it is a good recipient cell for exogenous gene expression. In this study, the expression plasmid pAN7-1 （containing promoter gpd-An derived from Aspergillus nidulans and selectable marker gene hph conferring resistance to hygromycin B） and plasmid pLg-hph （containing promoter gpd-Le derived from Lentinula edodes and selectable marker gene hph） were transformed into the yeast-like conidia of T. fuciformis by PEG-mediated protoplast transformation, respectively. The primary putative transformants were selected by the sandwich screening method with the selective medium containing 50 μg mL^-1 hygromycin. The putative transformants were obtained from the primary putative transformants transferred on PDSA plates containing 100 μg mL^-1 hygromycin for second round selection. Experimental results showed that the optimal concentration of PEG 4000 for mediating protoplast transformation was 25%. PCR and Southern blotting confirmed that the selectable marker gene hph was integrated effectively into the genome of the yeast-like conidia of T. fuciformis with plasmid pLg-hph transformation. Its transformation efficiency was 110 transformants per μg DNA, and the hph gene was integrated into the genome of some yeast-like conidia with plasmid pAN7-1 transformation. However, its transformation efficiency was only 9 transformants per μg DNA. The presence of hph gene in the genome of transformants after 5 generations of sub- culturing on PDSB medium was confirmed by PCR, suggesting that the foreign gene hph was stable during subculture.展开更多
目的:研究聚乙二醇(polyethylene glycol,PEG)对类弹性蛋白(elastin-like protein,ELP)ELP[I]40相变温度(inverse temperature transition,Tt)的影响。方法:设计并合成ELP[I]40基因(由40个(VPGIG)五肽单元串联组成),表达纯化后,检测不...目的:研究聚乙二醇(polyethylene glycol,PEG)对类弹性蛋白(elastin-like protein,ELP)ELP[I]40相变温度(inverse temperature transition,Tt)的影响。方法:设计并合成ELP[I]40基因(由40个(VPGIG)五肽单元串联组成),表达纯化后,检测不同浓度PEG条件下ELP[I]40的Tt。结果:在ELP[I]40终浓度为25μmol/L时,PEG浓度为5%,10%,15%,20%,25%时分别使Tt由29℃降至26.5℃,22℃,15.2℃,8.8℃,2.5℃。结论:PEG可降低ELP的Tt,可通过PEG促进ELP重组蛋白分离纯化。展开更多
【目的】使用自行设计的类弹性蛋白(Elastin-like protein,ELP)ELP[I]50作为非色谱纯化标签,分离纯化重组硫氧还蛋白(Thioredoxin,Trx),并研究聚乙二醇(Polyethyleneglycol,PEG)对ELP[I]50-Trx相变温度(Inverse temperature transition,...【目的】使用自行设计的类弹性蛋白(Elastin-like protein,ELP)ELP[I]50作为非色谱纯化标签,分离纯化重组硫氧还蛋白(Thioredoxin,Trx),并研究聚乙二醇(Polyethyleneglycol,PEG)对ELP[I]50-Trx相变温度(Inverse temperature transition,Tt)的影响。【方法】人工合成Trx基因,将其亚克隆到自行构建的表达载体pET28编码ELP[I]50标签下游,转入大肠杆菌BLR(DE3)进行表达。融合蛋白表达后,采用可逆相变循环(Inverse transitioncycling,ITC)分离纯化,并检测不同浓度PEG时的Tt值。【结果】成功表达、分离纯化出融合蛋白ELP[I]50-Trx,检测出该蛋白浓度为25μmol/L时,Tt为28.6°C;而当PEG的浓度为5%、10%、15%、20%时,Tt分别降至22.3°C、15.9°C、6°C、0°C。【结论】ELP[I]50标签高效纯化重组蛋白具有操作简便、成本较低、易于扩大的优势,而PEG能降低蛋白的Tt值,进一步增强分离纯化效果,扩大使用范围,可望应用于分离纯化多种重组蛋白。展开更多
PEGylated poly（2-（dimethylamino）ethyl methacrylate） with comb-like architecture was synthesized by two-step polymerization. First,poly（oligo（ethylene glycol） malicate）（POEGMA） bearing pendant hydroxyl groups...PEGylated poly（2-（dimethylamino）ethyl methacrylate） with comb-like architecture was synthesized by two-step polymerization. First,poly（oligo（ethylene glycol） malicate）（POEGMA） bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo（ethylene glycol） and malic acid in the presence of scandium triflate as chemoselective catalyst.Then the poly（2- （dimethylamino）ethyl methacrylate） side chains were grafted from the POEGMA backbone by atom transfer radical polymerization （ATRP） after the hydroxyl groups were modified into bromo-ester form,resulting in a PEGylated cationic copolymer with branched architecture.展开更多
Cross-linked PEG-based copolymers were obtained via synthesis of polyethylene glycol （PEG） and methoxy polyethylene glycol （MPEG） by the bridging and/or cross-linking agent of 2,4-tolylene diisocyanate （TDI） and...Cross-linked PEG-based copolymers were obtained via synthesis of polyethylene glycol （PEG） and methoxy polyethylene glycol （MPEG） by the bridging and/or cross-linking agent of 2,4-tolylene diisocyanate （TDI） and/or hexamethylene-l,6-diisocyanate homopolymer （HDI trimer）. The effects on the crystallization behaviors of the samples could be found with the changes in molecular weight of MC-PEG and molecular weight of SC-PEG in certain cross-linked density. It is revealed that the samples appear not to crystallize when the molecular weight of MC-PEG and SC-PEG are 1000 g/mol or less than that. The samples begin to crystallize when the molecular weight of either MC-PEG or SC-PEG reaches 2000 g/mol. The crystallinity of crystallized MC-PEG decreases with the increasing molecular weight of uncrystallized SC-PEG and the crystallinity of crystallized SC-PEG declines with the rise of molecular weight of uncrystallizable MC-PEG. The chains of SC-PEG （M_n = 2000 g/mol） can fold and align easilier than those of MC-PEG （M_n = 2000 g/mol）, when the content of PEG is the same.展开更多
基金Funded by the National Natural Science Foundation of China (No.1997207150274065) and the Special Funds for Major State Basic Research Project (No.2002CB412704)
文摘The synthesis and characterization of PEG-like macromolecular structures on Nit inol surface from tri (ethylene glycol) dimethyl-ether under ECR-cold-plasma conditions were discussed. It was demonstrated that based on high-resolution ES CA, ATR-FTIR and contact angle investigations, the deposited PEG-like layers a re composed mainly of -CH 2-CH 2-O- linkages. These structures have a relati vely low contact angle. Compared to the unmodified surfaces, the plasma-treated Nitinol surfaces are more hydrophilic. Plasma enhanced coatings of PEG-like la yers can prevent Ni ion from releasing, thereby improving the biocompatibility o f Nitinol.
基金National Natural Science Foundation of China(No.30670562)Hubei Provincial Department of Education:Science Research Project(No.D200515009)
文摘A poly（ethylene glycol） （PEG-like） coating was developed to improve the biocom- patibility of Nickel-Titanium （NiTi） alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a room temperature of 298 K through a ECR （electron-cyclotron resonance） cold-plasma enhanced chemical vapor deposition method using tetraglyme （CH3-O- （CH2-CH2-O）4-CH3） as a precursor. A power supply with a frequency of 2.45 GHz was applied to ignite the plasma with Ar（argon） used as the carrier gas. Based on the atomic force microscopy （AFM） studies, a thin smooth coating on NiTi substrates with highly amorphous functional groups on the modified NiTi surfaces were mainly the same accumulated stoichiometric ratio of C and O with PEG. The vitro studies showed that platelet-rich plasma （PRP） adsorption on the modified NiTi alloy surface was significantly reduced. This study indicated that plasma surface modification changes the surface components of NiTi alloy and subsequently improves its biocompatibility.
文摘A water soluble hydroxy-capped comb-like poly(ethylene glycol)(CPEG) was prepared via atom transfer radical polymerization(ATRP).A stable CPEG coating was obtained via dip-coating followed by curing at 70℃ for 48 h.The CPEG-modified surface was proved to be stable in both aqueous environment and ambient according to contact angle behavior and weight decrement testing.The coating forming mechanism was investigated through FTIR,the spectra data demonstrated the stability of CPEG coating derived from its hydrogen bond of inter-molecules and intra-molecules.Platelet experiment showed CPEG modified surface reacted extremely weakly with platelet and showed excellent thrombus resistance than that of both on the pure PET surface and PET surface modified with linear PEG.The model drug RD6G was applied to fabricate a drug-buried CPEG coating surface.The drug-releasing curve demonstrated the stability of the CPEG coating and the controlled-release behavior of RD6G.The unique property of CPEG coating surface provided the potential application in the immobilization and release of aqueous drug,including protein and peptide.
基金funded by the National Hi-Tech Research and Development Program of China (863 Program,2006AA10Z301)the National Natural Science Foundation of China (30371000, 30671457)
文摘Tremellafuciformis is one of higher basidiomycetes. Its basidiospore can reproduce yeast-like conidia, which is also called the blastospore by budding. The yeast-like conidia of T. fuciformis is monokaryotic and easy to culture by submerged fermentation similar to yeast. Thus, it is a good recipient cell for exogenous gene expression. In this study, the expression plasmid pAN7-1 （containing promoter gpd-An derived from Aspergillus nidulans and selectable marker gene hph conferring resistance to hygromycin B） and plasmid pLg-hph （containing promoter gpd-Le derived from Lentinula edodes and selectable marker gene hph） were transformed into the yeast-like conidia of T. fuciformis by PEG-mediated protoplast transformation, respectively. The primary putative transformants were selected by the sandwich screening method with the selective medium containing 50 μg mL^-1 hygromycin. The putative transformants were obtained from the primary putative transformants transferred on PDSA plates containing 100 μg mL^-1 hygromycin for second round selection. Experimental results showed that the optimal concentration of PEG 4000 for mediating protoplast transformation was 25%. PCR and Southern blotting confirmed that the selectable marker gene hph was integrated effectively into the genome of the yeast-like conidia of T. fuciformis with plasmid pLg-hph transformation. Its transformation efficiency was 110 transformants per μg DNA, and the hph gene was integrated into the genome of some yeast-like conidia with plasmid pAN7-1 transformation. However, its transformation efficiency was only 9 transformants per μg DNA. The presence of hph gene in the genome of transformants after 5 generations of sub- culturing on PDSB medium was confirmed by PCR, suggesting that the foreign gene hph was stable during subculture.
文摘目的:研究聚乙二醇(polyethylene glycol,PEG)对类弹性蛋白(elastin-like protein,ELP)ELP[I]40相变温度(inverse temperature transition,Tt)的影响。方法:设计并合成ELP[I]40基因(由40个(VPGIG)五肽单元串联组成),表达纯化后,检测不同浓度PEG条件下ELP[I]40的Tt。结果:在ELP[I]40终浓度为25μmol/L时,PEG浓度为5%,10%,15%,20%,25%时分别使Tt由29℃降至26.5℃,22℃,15.2℃,8.8℃,2.5℃。结论:PEG可降低ELP的Tt,可通过PEG促进ELP重组蛋白分离纯化。
文摘【目的】使用自行设计的类弹性蛋白(Elastin-like protein,ELP)ELP[I]50作为非色谱纯化标签,分离纯化重组硫氧还蛋白(Thioredoxin,Trx),并研究聚乙二醇(Polyethyleneglycol,PEG)对ELP[I]50-Trx相变温度(Inverse temperature transition,Tt)的影响。【方法】人工合成Trx基因,将其亚克隆到自行构建的表达载体pET28编码ELP[I]50标签下游,转入大肠杆菌BLR(DE3)进行表达。融合蛋白表达后,采用可逆相变循环(Inverse transitioncycling,ITC)分离纯化,并检测不同浓度PEG时的Tt值。【结果】成功表达、分离纯化出融合蛋白ELP[I]50-Trx,检测出该蛋白浓度为25μmol/L时,Tt为28.6°C;而当PEG的浓度为5%、10%、15%、20%时,Tt分别降至22.3°C、15.9°C、6°C、0°C。【结论】ELP[I]50标签高效纯化重组蛋白具有操作简便、成本较低、易于扩大的优势,而PEG能降低蛋白的Tt值,进一步增强分离纯化效果,扩大使用范围,可望应用于分离纯化多种重组蛋白。
基金the financial supports from the Major State Basic Research Project(No. 2011CB606001)the Committee of Science and Technology of Zhejiang Provincea project supported by Scientific Research Fund of Ztiejiang Provincial Education Department(No.Y201121828)
文摘PEGylated poly（2-（dimethylamino）ethyl methacrylate） with comb-like architecture was synthesized by two-step polymerization. First,poly（oligo（ethylene glycol） malicate）（POEGMA） bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo（ethylene glycol） and malic acid in the presence of scandium triflate as chemoselective catalyst.Then the poly（2- （dimethylamino）ethyl methacrylate） side chains were grafted from the POEGMA backbone by atom transfer radical polymerization （ATRP） after the hydroxyl groups were modified into bromo-ester form,resulting in a PEGylated cationic copolymer with branched architecture.
基金financially supported by the National Natural Science Foundation of China(Nos.51173130,21374077 and 51573131)
文摘Cross-linked PEG-based copolymers were obtained via synthesis of polyethylene glycol （PEG） and methoxy polyethylene glycol （MPEG） by the bridging and/or cross-linking agent of 2,4-tolylene diisocyanate （TDI） and/or hexamethylene-l,6-diisocyanate homopolymer （HDI trimer）. The effects on the crystallization behaviors of the samples could be found with the changes in molecular weight of MC-PEG and molecular weight of SC-PEG in certain cross-linked density. It is revealed that the samples appear not to crystallize when the molecular weight of MC-PEG and SC-PEG are 1000 g/mol or less than that. The samples begin to crystallize when the molecular weight of either MC-PEG or SC-PEG reaches 2000 g/mol. The crystallinity of crystallized MC-PEG decreases with the increasing molecular weight of uncrystallized SC-PEG and the crystallinity of crystallized SC-PEG declines with the rise of molecular weight of uncrystallizable MC-PEG. The chains of SC-PEG （M_n = 2000 g/mol） can fold and align easilier than those of MC-PEG （M_n = 2000 g/mol）, when the content of PEG is the same.
