生物活性复合材料在生物矿化过程中的微观形貌与离子浓度变化

采用3-羟基丁酸酯-3-羟基戊酸酯的共聚物(PHBV)与磷酸三钙(TCP)、羟基磷灰石(HA)、生物活性玻璃(BG)等进行复合,获得了性能优良的生物活性骨组织工程支架材料和骨修复材料.研究和比较了3种复合材料在体外模拟生理环境中发生的生物矿化反应,对比了反应前后因矿化物的形成导致的表面微观形貌的变化,通过检测反应液离子浓度的变化对不同材料的矿化过程和生物活性进行了定量表征.研究结果表明,3种复合材料在模拟生理溶液中发生生物矿化的过程和程度不同,其中PHBV/BG的生物活性反应最为明显.     

PHBV纳米纤维的静电纺丝及在生物医用领域的研究进展

聚(3-羟基丁酸酯-3-羟基戊酸酯)(PHBV)纳米纤维具有高比表面积、高孔隙率、生物相容性、生物降解性等优点,可用作生物医用材料.本文综述了基于静电纺丝法制备的PHBV纳米纤维及其在生物医用领域的研究进展,讨论了PHBV纺丝溶液的溶剂、浓度、外加盐类以及聚合物等对PHBV纳米纤维形貌、结构及性能的影响规律,结合目前P...     

CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料在SBF中的性能研究

利用溶胶-凝胶生物活性材料粉末二次烧结工艺,制备了CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料,并利用体外实验(in vitro)方法和XRD,SEM及FTIR技术研究了此烧结材料的显微形貌、晶相、生物活性和可降解性能.结果表明,经800℃烧结5 min后,有少量硅磷酸钙[Ca5(PO4)2SiO4,5CPS]析出,在模拟体液(SBF)中浸泡,随着时间的增长,材料表面最初形成的无定形钙磷化合物矿化成碳酸羟基磷灰石(HCA)纳米团簇,并逐渐相互融合形成HCA覆盖层;HCA只在烧结体的玻璃相(SG相)表面生成,在5CPS微晶相表面未发现HCA,该材料在37℃恒温的SBF溶液中具有较高的生物活性和可降解性能.     

PHBV-GMA与PHBV-GMA/PPC共混物中接枝物的热性能与形态结构

以甲基丙烯酸缩水甘油酯(GMA)单体对聚(3-羟基丁酸酯-3-羟基戊酸酯)(PHBV)接枝改性,得到的产物PHBV-GMA与封端后的聚碳酸亚丙酯(PPC)反应性共混。索氏抽提器提取PHBV-GMA和PHBV-GMA/PPC共混物,分别得到两种接枝产物PHBV-g-GMA和PHBV-g-PPC,用差示扫描量热法(DSC)、偏光显微镜(POM)以及原子力显微镜(AFM)研究其热性能和形态结构。结果发现,GMA接枝后,对PHBV结晶有成核效应。PPC接枝PHBV后,接枝物PHBV-g-PPC结晶度降低,球晶尺寸减小,PHBV和PPC两种大分子间的相分离程度降低,相容性明显提高。     

羟基磷灰石在磺化聚醚苯并咪唑薄膜表面的生长

以聚[2,2′-(对氧基联苯)-5,5′-苯并咪唑](OPBI)及其磺化产物磺化聚[2,2′-(对氧基联苯)-5,5′-苯并咪唑](SOPBI)薄膜作为基体, 采用交替沉积和模拟体液(SBF)浸泡相结合的方法快速在薄膜表面沉积羟基磷灰石层. 采用选区电子衍射(SAED)和衰减全反射傅里叶变换红外光谱(ATR-FTIR)对羟基磷灰石(HA)的晶体结构进行了分析. 用扫描电子显微镜(SEM)对整个沉积过程中羟基磷灰石的形态变化进行了跟踪. 实验结果表明, SOPBI薄膜诱导HA沉积的速率明显快于OPBI薄膜. SOPBI的磺酸基团不但提供了固定Ca²⁺的负电表面, 而且还有助于咪唑基团对Ca²⁺的固定. 而缺失磺酸基团的OPBI在不同pH值的交替沉积溶液中的电离形式阻碍了咪唑基团对Ca²⁺和HPO₄^2-的作用, 且未能在SBF浸泡过程中得到改善.     

含硅磷酸钙骨水泥的理化性质及体外细胞毒性

用共沉淀反应法制备硅酸三钙(C3S),将所制备的硅酸三钙(C3S)加入到磷酸钙系骨水泥(CPC)中,制备了一种新型的硅磷酸钙骨水泥(CPSC).研究了该复合骨水泥的理化性质和体外细胞毒性.与CPC骨水泥相比,硅磷酸钙骨水泥(CPSC)的固化时间延长,添加适量的C3S可提高CPC的抗压强度;在模拟体液(SBF)浸泡设定时间后,硅磷酸钙骨水泥(CPSC)降解率增加,并且在浸泡初期,SBF的pH增加.体外细胞毒性实验结果显示:复合C3S骨水泥浸提液能促进成纤维细胞的增殖,表明硅磷酸钙骨水泥有良好的生物相容性.含C3S的磷酸钙骨水泥可作为骨组织再生的生物材料使用.     

CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料在SBF中的性能研究

利用溶胶-凝胶生物活性材料粉末二次烧结工艺,制备了CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料,并利用体外实验（in vitro）方法和XRD,SEM及FTIR技术研究了此烧结材料的显微形貌、晶相、生物活性和可降解性能.结果表明,经800℃烧结5 min后,有少量硅磷酸钙[Ca5（PO4）2SiO4,5CPS]析出,在模拟体液（SBF）中浸泡,随着时间的增长,材料表面最初形成的无定形钙磷化合物矿化成碳酸羟基磷灰石（HCA）纳米团簇,并逐渐相互融合形成HCA覆盖层;HCA只在烧结体的玻璃相（SG相）表面生成,在5CPS微晶相表面未发现HCA,该材料在37℃恒温的SBF溶液中具有较高的生物活性和可降解性能.     

钛基多孔HA/SiO2复合涂层的制备及性能研究

为了制得表面多孔且与基材结合强度高的羟基磷灰石(HA)涂层,实验中以正丁醇为分散介质,以SiO2粉末为添加剂,纯钛片为基材,电泳沉积制备羟基磷灰石/二氧化硅/壳聚糖/(HA/SiO2/CS)复合涂层,经后续热处理得到多孔HA/SiO2复合涂层,采用扫描电镜(SEM)、傅立叶红外光谱仪(FT-IR)、X射线衍射仪(XRD)、万能材料试验机对涂层的表面形貌、组成、结构和结合强度进行测试和表征,并通过模拟体液(SBF)浸泡法对复合涂层的生物活性进行评价.结果表明:当悬浮液中的HA/SiO2/CS质量比为1∶1∶1时,制得的HA/SiO2/CS涂层经700℃热处理后获得的HA/SiO2复合涂层孔洞分布均匀,大孔孔径在10～15μm,小孔孔径在1～5μm;涂层与基材的结合强度达到25.5 MPa;多孔HA/SiO2复合涂层在SBF中浸泡7 d后,涂层表面碳磷灰石化;说明实验中添加SiO2所制得的多孔HA/SiO2复合涂层与钛基材结合强度高,且具有良好的生物活性.     

聚(3-羟基丁酸酯-co-3-羟基戊酸酯)改性及纤维成形北大核心CSCD

聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PHBV)是一种微生物发酵生产的热塑性聚合物。从物理、化学改性及其纤维成形两个方面综述了PHBV的研究进展。PHBV的物理改性主要有无机纳米粒子共混体系(PHBV/iNPs)、有机纳米晶共混体系(PHBV/oNPs)、高聚物共混体系(PHBV/Polymer)和绿色全降解共混体系;化学结构构筑主要包括接枝共聚改性、嵌段共聚改性、端基扩链改性等。从改性的手段及介质,分析了改性方法的优缺点。PHBV纤维的成形方法主要有熔融纺丝法、干法纺丝法及静电纺丝法。从PHBV纤维应用领域看,熔融纺纤维应用目标在于替代现有石油基相关产品,而静电纺纤维主要应用于开拓组织工程再生医学领域。最后,对PHBV今后的研究及发展提出了展望。     

2-氨基-3-羟基吡啶-过氧化氢-辣根过氧化物酶伏安酶联免疫体系分析人血清癌胚抗原

以氮杂环化合物为电化学分析底物的2-氨基-3-羟基吡啶-H2O2-辣根过氧化物酶(HRP)伏安酶联免疫体系测定人血清癌胚抗原(CEA).HRP催化H2O2氧化2-氨基-3-羟基吡啶的酶促反应产物,在缓冲液中-0.36 V处产生一个灵敏的伏安还原峰,借助此峰可以测定游离的HRP,进而可用于以HRP为标记物的酶联免疫分析.对酶促反应条件和测定条件的优化反应条件为:以B-R缓冲液(pH 6.0)为反应介质,在10 mL总反应液中含有1.0 mL 0.2 mol/L B-R缓冲液、3.0 mL 8.0 mmol/L 2-氨基-3-羟基吡啶溶液以及1.5 mL 0.5 mmol/L H2O2溶液,反应温度37 ℃,反应时间30 min.最佳测定条件为:B-R缓冲液(pH 7.0)为支持电解质,在10 mL总测定溶液中含有5 mL上述总反应液、1.0 mL 0.2 mol/L B-R缓冲液.测定仪器条件:起始电位0.00 V,终止电位-0.80 V,电位扫描速度400 mV/s,滴汞静止时间7 s.在最佳的反应条件和测定条件下,新体系测定游离HRP的线性范围为4.0×10-4～1.0 μg/L; 对HRP的检出限为0.12 ng/L.新体系对CEA测定的线性范围为0.50～80.0 μg/L; 检出限为0.50 μg/L.为经典ELISA法的检出限的1/10.     

聚羟基烷酸酯酶降解动力学研究

研究了羟基丁酸 羟基戊酸共聚物 (PHBV)在脂肪酶中的降解行为 ,用滴定法测定降解速度并进行酶促反应动力学研究 .探讨了降解速度与酶浓度和底物浓度的数学关系和Michaelis Menten常数 ,从实验上和理论上证实了PHBV的物理形态和几何尺寸对酶降解过程的影响 ,以及实验数据与非均相动力学模型的拟合     

Thermal and mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) plasticized by biodegradable soybean oils

The effects of soybean oil (SO) and epoxidized soybean oil(ESO) as biodegradable plasticizers for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were studied using thermal and mechanical analyses. PHBV/SO and PHBV/ESO blends were prepared by evaporating solvent from blend solutions. The levels of additive in the blend varied from 5% to 30%. As a plasticizer for PHBV, ESO was more effective than SO in depression of the glass transition temperature as well as in increasing the elongation at break and the impact strength of the films with increasing levels of additive. Biodegradation of the plasticized PHBV films was carried out by accelerated compost method. The degradation rates of the blend films with SO or ESO were found to be faster than that of PHBV film. From the thermogravimetric analysis, it was found that the thermal reaction between the epoxide groups of ESO and PHBV fragments with carboxylic chain ends, occurred during the degradation of PHBV/ESO blends.     

STUDY ON BIODEGRADABILITY OF POLY (3-HYDROXYBUTYRATE-co-3-HYDROXYVALERATE)/ORGANOPHILIC MONTMORILLONITE NANOCOMPOSITES

1. INTRODUCTION Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has been recognized as apotential environment-friendly substitute for traditional plastics. The structure, mechanicalproperties and biodegradability of PHBV as biodegradable plastic have been reported by many groups [1-3]. However, PHBV presents some problems, such as high cost, slow crystallization rate, relatively difficult processing and high degree of crystallinity. Therefore, it is difficult to use PHBV widel…     

STUDY ON BIODEGRADABILITY OF POLY（3-HYDROXYBUTYRATE-co-3-HYDROXYVALERATE）／ORGANOPHILIC MONTMORILLONITE NANOCOMPOSITES

Poly (3-lydroxybutyrate-co-3-hydroxyvalerate)/Organophilic montmorillonite(PHBV/OMMT) nanocomposites were prepared and the biodegradability of the PHBV/OMMT nanocomposites was studied by a cultivation degrading method in soil suspension The relationship between structure and biodegradability of PHBV/OMMT nanocomposites was investigated. The results showed that the biodegradability of PHBV/OMMT nanocomposites decreased with increasing amount of OMMT and it was related to the number of PHBV degrading microorganisms in degradation environment, the anti-microbial property of OMMT and the degree of crystallinity of the nanocomposites.     

Superhydrophobicity of PHBV fibrous surface with bead-on-string structure

A poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibrous surface with various bead-on-string structures was fabricated by electrospinning. PHBV was electrospun at various concentrations and then CF4 plasma treatment was employed to further improve the hydrophobicity of the PHBV fiber surfaces. The surface morphology of the electrospun PHBV mats was observed by scanning electron microscopy (SEM). The surface properties were characterized by water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). The surface morphology of the electrospun PHBV fibrous mats with the bead-son-string structure varied with the solution concentration. The WCA of all of the electrospun PHBV mats was higher than that of the PHBV film. In particular, a very rough fiber surface including porous beads was observed when PHBV was electrospun from the solution with a concentration of 26 wt%. Also, its WCA further increased from 141 degrees to 158 degrees after CF(4) plasma treatment for 150 s. PHBV can be rendered superhydrophobic by controlling the surface morphology and surface energy, which can be achieved by adjusting the electrospinning and plasma treatment conditions.     

造孔剂对电泳沉积制备多孔HA涂层及其生物活性的影响

采用水热法制得的羟基磷灰石(HA)纳米粉体,分别与造孔剂葡萄糖(Glu)、壳聚糖(CS)、炭粉(C)3种微粒(＜38.5 μm)配置成质量比1∶1的悬浮液,电泳沉积 烧结制备钛基多孔HA涂层,并对制得的3种多孔HA涂层在模拟体液浸泡前后的表面形貌、化学组成及物相变化进行表征。 结果表明,经700 ℃烧结处理后制得的3种多孔HA涂层在1.5倍人体模拟体液中浸泡5 d后,多孔HA涂层表面均被层状生长的碳磷灰石颗粒完全覆盖,颗粒直径在5~25 μm,说明这些多孔HA涂层均具有良好的生物活性。 其中以CS为造孔剂制得的多孔HA涂层结合强度最高,达19.5 MPa,有望开发成为新型的人骨植入生物陶瓷材料。     

Thermal properties and degradability of poly(propylene carbonate)/poly(β-hydroxybutyrate-co-β-hydroxyvalerate) (PPC/PHBV) blends

Poly(propylene carbonate)/poly(β-hydroxybutyrate-co-β-hydroxyvalerate) (PPC/PHBV) blends were prepared via the solution casting method at different proportions. Their thermal characteristics were studied by means of differential scanning calorimetry (DSC) and thermogravimetry (TG). The degradability of the blends was investigated in soil suspension cultivation and in vitro degradation testing. The changes of structure and molecular weight for blends were also studied by ¹H nuclear magnetic resonance spectroscopy (¹H NMR), scanning electron microscopy (SEM) and gel permeation chromatography (GPC) before and after degradation. Although the PPC/PHBV blends were immiscible, the addition of PHBV could improve the thermal stability of PPC. PHBV was degraded mainly by the action of microbial enzymes in the soil suspension, which biodegraded it more rapidly than PPC in a natural environment. PPC was degraded mainly by chemical hydrolysis and random hydrolytic scission of chains in the PBS solution in vitro, and degradation of PPC was more rapid than that of PHBV in a simulated physiological environment.     

Design and Construction of 3D Porous Na3V2(PO4)3/C as High Performance Cathode for Sodium Ion Batteries

An easy and delicate approach using cheap carbon source as conductive materials to construct 3D sequential porous structural Na3V2(PO4)3/C(NVP/C)with high performance for cathode materials of sodium ion battery is highly desired.In this paper,the NVP/C with 3D sequential porous structure is constructed by a delicate approach named as“cooking porridge”including evaporation and calcination stages.Especially,during evaporation,the viscosity of NVP/C precursor is optimized by controlling the adding quantity of citric acid,thus leading to a 3D sequential porous structure with a high specific surface area.Furthermore,the NVP/C with a 3D sequential porous structure enables the electrolyte to interior easily,providing more active sites for redox reaction and shortening the diffusion path of electron and sodium ion.Therefore,benefited from its unique structure,as cathode material of sodium ion batteries,the 3D sequential porous structural NVP/C exhibits high specific capacities(115.7,88.9 and 74.4 mA·h/g at current rates of 1,20 and 50 C,respectively)and excellent cycling stability(107.5 and 80.4 mA·h/g are remained at a current density of 1 C after 500 cycles and at a current density of 20 C after 2200 cycles,respectively).     

可降解自固化类骨磷灰石支架的研究

0引言一直以来,钙磷生物材料如羟基磷灰石(hy-droxyapatite,HA)由于其成份与骨的无机成份相似,具有良好的生物相容性,作为骨修复材料引起了人们广泛的兴趣。磷酸钙骨水泥是一类可在生理条件下自固化的非陶瓷型类HA人工骨材料,这种由磷酸钙骨水泥(calcium phosphate cement,CPC)转变而成的HA,与天然骨磷灰石有类似的组成结构,植入人体后可参与新陈代谢,促进骨组织生长[1,2]。一些研究显示,CPC具有成骨活性和生物降解性,在体内被吸收的同时可引导新骨的生成,从而可克服自体骨、磷酸三钙陶瓷因吸收降解过快造成的局部缺陷以及陶瓷型HA长…