改性羟基磷灰石/聚乳酸纳米复合材料的结晶行为

利用溶剂复合的方法制备了具有良好生物相容性的表面接枝聚(γ-苄基-L-谷氨酸)的改性羟基磷灰石/聚乳酸纳米复合材料, 并研究了其熔融与结晶行为. 结果表明, 聚乳酸的玻璃化转变温度为60.3 ℃, 而复合材料的玻璃化转变温度达到65.8 ℃, 不同样品在140 ℃等温结晶后, 改性羟基磷灰石/聚乳酸复合材料的球晶直径仅为聚乳酸(PLLA)球晶直径的16.7%~66.7%. 复合材料的熔点提高到184.4 ℃.     

聚乙烯醇/纳米羟基磷灰石复合材料微型注塑研究

结合固相剪切碾磨和分子复合技术制备了适合于微型注塑加工的聚乙烯醇/纳米羟基磷灰石(PVA/n-HA)复合材料,实现了n-HA含量达30%的PVA/n-HA复合材料的微型注塑加工。采用差示扫描量热法(DSC)、热重分析仪(TGA)和高压毛细管流变仪研究了PVA/n-HA复合材料的热性能和流变性能,结果表明:改性PVA/n-HA复合材料的熔点降低,热分解温度升高,获得120℃以上的热塑加工窗口;PVA/n-HA复合材料呈现剪切变稀特性,在高剪切速率下具有较低的熔体粘度,适合微型注塑加工,具有良好的充模性能。采用扫描电子显微镜(SEM)和X射线衍射(XRD)研究了PVA/n-HA微型注塑样品的结构与性能,结果表明n-HA均匀分散于PVA基体中,提高了复合材料的尺寸稳定性;受微型注塑过程中高剪切应力诱导结晶作用的影响,PVA/n-HA微型注塑样品的结晶度高于常规注塑样品的结晶度。     

多孔纳米羟基磷灰石-聚乳酸复合材料的

本文以TIPS法,在溶液中制备得到多孔纳米羟基磷灰石-聚乳酸复合材料,并对无机相与有机相之间的界面结合情况进行了研究,结果表明纳米羟基磷酸钙与聚乳酸基体之间结合良好。     

聚乙烯醇/明胶/纳米羟基磷灰石复合材料热塑加工性能研究

结合固相剪切碾磨技术(S3M),以胶原纤维(Col)在熔融挤出过程中原位降解成明胶(Gel),通过Gel与聚乙烯醇(PVA)分子间形成氢键复合增塑PVA,改善聚乙烯醇/纳米羟基磷灰石(PVA/n-HA)复合材料的热塑加工性能.采用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)、示差扫描量热仪(DSC)、热重分析仪(TGA)、X射线衍射仪(XRD)和高压毛细管流变仪等研究了复合材料的结构与热塑加工性能.结果表明,通过S3M技术实现了n-HA在PVA基体中的均匀分散;FTIR表明Gel与PVA间形成了氢键作用和部分接枝反应;Gel和PVA分子间的氢键作用使PVA/Gel/n-HA复合材料的初始分解温度提高到287.6℃,改善了PVA的热稳定性,PVA的结晶度由纯PVA的58.2%降低到复合材料中的24.5%,使其熔点降低至130.5℃,拓宽了PVA/n-HA复合材料的加工范围,获得超过140 K的热塑加工窗口.Gel有效降低了PVA/nHA复合材料表观黏度,改善了PVA/n-HA复合材料的热塑加工性能.     

硬脂酸改性纳米羟基磷灰石表面性能的研究

采用硬脂酸(C₁₇H₃₅COOH)对纳米羟基磷灰石(n-HA)表面进行处理,并研究了n-HA与C₁₇H₃₅COOH的界面作用。透射电子显微镜(TEM)、傅立叶红外光谱(FTIR)以及X光电子能谱(XPS)分析表明,C₁₇H₃₅COOH在n-HA表面黏附,其中羧酸根离子(-COO^-)与钙离子(Ca^2＋)之间形成了稳定的离子键,以羧酸钙形式存在。C₁₇H₃₅COOH改性后的n-HA与聚碳酸酯(PC)复合后,复合材料的力学性能与未改性n-HA相比有明显提高。扫描电子显微镜(SEM)结果显示,经处理后的HA微粒在PC中分散均匀,两者间结合紧密,无明显界面,复合材料的断裂呈明显的韧性断裂,随着n-HA无机粒子含量增加,复合材料的断裂也逐渐向韧性与脆性断裂共存转变。     

化学沉淀法制备羟基磷灰石纳米粒子

采用化学沉淀法以 Ca(NO3 ) 2 · 5 H2 O和 (NH4) 2 HPO4为主要原料 ,制备了短棒状或针状的羟基磷灰石纳米粒子 (HA) ,考察了各反应参数对纳米粒子性能的影响 ,并由透射电镜、X射线晶体衍射、电子衍射、红外、比表面积等手段对其进行表征。实验结果表明 ,所制备的 HA粒子粒径长约 30～5 0 nm,直径约 10～ 15 nm;通过严格控制各反应参数可以基本上实现纳米羟基磷灰石粒子粒径、形态等部分性质的可控制备     

改性纳米羟基磷灰石/PLGA复合材料的制备及生物活性

以低聚乳酸接枝改性的羟基磷灰石纳米粒子(op-HA)和聚丙交酯-乙交酯(PLGA)制备的生物可降解纳米复合材料(op-HA/PLGA)为研究对象, 采用FTIR, TGA, ESEM和EDX分析其接枝反应、接枝率、表面形貌和钙磷沉积情况, 通过在材料膜表面接种兔成骨细胞进行体外培养, 采用荧光染色、NIH Image J图像分析和Real-time PCR综合评价细胞在材料表面的形态、黏附面积比、增殖能力和基因表达水平, 以此评价新型骨修复纳米复合材料op-HA/PLGA的表面性质和生物活性. 研究结果表明, op-HA的表面接枝率为8.3%, 掺入至PLGA后可形成富含钙磷的粗糙表面, 促进成骨细胞的黏附、扩展和增殖, 提高Ⅰ型胶原蛋白(Collagen-Ⅰ)、骨形态蛋白-2(BMP-2)和骨连接蛋白(Osteonectin)的基因表达水平, 提高材料的钙磷沉积能力. op-HA/PLGA具有良好的细胞相容性和成骨活性.     

利用溶剂热压方法制备羟基磷灰石多孔纳米固体

利用溶剂热压方法,以羟基磷灰石（HAP）纳米颗粒为原料制备了一种介于纳米粉体和纳米陶瓷体之间的过渡态——体块HAP多孔纳米固体,并用X射线衍射（XRD）、扫描电子显微镜（SEM）、压汞仪和热分析（DSC和TGA）等方法对样品进行了表征,初步研究了溶剂的种类、分布均匀性等因素对HAP多孔纳米固体的孔容和孔径分布的影响,并对HAP多孔纳米固体的热稳定性进行了分析.     

聚乳酸/羟基磷灰石多孔复合材料的制备及体外降解研究

采用溶剂浇铸-盐沥洗法制备了具有较高孔隙率的聚左旋乳酸/羟基磷灰石(PLLA/HA)多孔复合材料,用扫描电镜(SEM)和衰减全反射-傅立叶变换红外光谱(ATR-FTIR)研究了HA含量对制备样品的形貌以及体外降解行为的影响.结果表明,100/10、100/20、100/30、100/40和100/50的PLLA/HA复...     

水热重结晶法制备羟基磷灰石纳米棒

本文以Ca(NO₃)₂和(NH₄)₂HPO₄为原料，采用重结晶法，在水热条件下制备了羟基磷灰石(HA)纳米棒；利用X-射线衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)、红外光谱(FTIR)等分析测试手段，研究了pH值和晶化时间对HA组成和结构的影响。实验结果表明，室温混合pH值为7.5的沉淀物和pH值为10.5的清液，于180 ℃下水热处理10 h重结晶制得的HA纳米棒的平均长径比最长(约为28)；采用不同pH值的清液，体系的单体浓度(即化学势)改变时，得到的HA纳米棒的长径比不同；随着晶化时间延长，纳米棒的长径比先增大后减小。     

羟基磷灰石／胶原／植物多酚复合材料的研究

以原花色素、茶多酚等植物多酚为交联剂,采用低温原位合成法制备羟基磷灰石/胶原/植物多酚(HA/COL/PP)复合材料。对材料的形貌、热稳定性、溶胀性质进行了表征。结果表明,植物多酚的加入使复合材料中各成分结合更紧密,增加了复合材料的热稳定性,降低了复合材料的溶胀度。比较研究表明,添加原花色素对上述性能的改善更有效。为了考察加入植物多酚后复合材料的生物活性,分别对羟基磷灰石/胶原/原花色素(HA/COL/PA)、羟基磷灰石/胶原/茶多酚(HA/COL/TP)复合材料进行了体外矿化能力研究,观察到两种材料的表面都形成了新的矿化沉积层,说明加入了植物多酚不影响复合材料的体外矿化能力。因而,羟基磷灰石/胶原/植物多酚复合材料是一种有潜力的骨替代材料。     

Influence of alumina reinforcement on nano-hydroxyapatite/biopolymer composite for biomedical applications

The foremost material that closely mimics the mineral part of the bone tissue, and is therefore suitable for bone replacement, is nano-hydroxyapatite (nHAp) which exhibits low fracture toughness, and can be used for load-bearing scaffolds in biomedical applications. Therefore, for improved biomechanical features, composite materials are developed. This work focuses on the influence and contribution of bioactive alumina and nHAp on the biopolymer, i.e., gelatin matrix for the fabrication of load-bearing bone replacement composites. Incorporation of bioceramics alumina at the strengthening phase is essential for the improvement of mechanical properties for biomedical applications. The porosity of scaffolds varied from 79 to 85%. Fourier transform infrared (FTIR) and X-ray powder diffraction (XRD) analyses showed the presence of molecular interactions and chemical linkages between gelatin matrix, alumina, and nHAp particles. The compressive strength of alumina-reinforced nanocomposites scaffolds is three times higher than those of nHAp/gelatin. The elemental composition of the chemically synthesized nHAp particles was determined by SEM, FTIR, and XRD analyses.     

Preparation and characterization of collagen/chitosan poly (ethylene glycol)/nanohydroxyapatite composite scaffolds

Porous three‐dimensional collagen/chitosan scaffolds combined with poly (ethylene glycol) (PEG) and hydroxyapatite were obtained through a freeze‐drying method. Physical cross‐linking was examined by dehydrothermal treatment. The prepared materials were characterized by different analyses, eg, scanning electron microscopy (SEM), measurements of porosity and swelling, mechanical properties, and resistance to enzymatic degradation. The porosity of scaffolds and their swelling ratio decreased with the addition of hydroxyapatite. Moreover, after exposure to collagenase, the collagen/chitosan matrices containing PEG showed much faster degradation rate than matrices with the addition of hydroxyapatite. The results indicated that the addition of hydroxyapatite led to improvement of stiffness. The highest degree of porosity and swelling were demonstrated by collagen/chitosan/PEG matrices without hydroxyapatite.     

中空羟基磷灰石的制备方法研究进展

中空结构的羟基磷灰石因具备出色的生物相容性及生物活性、大比表面积和孔体积、小尺寸、良好的机械性、热稳定性以及表面渗透性等性能优点,让其在生物、医学、材料领域产生巨大影响,具有极大的运用价值.因此,制备具有中空结构的羟基磷灰石的方法及有关性能研究成为了热点.本文对例如模板法、水热法、溶剂热法、喷雾干燥法、微波协助法、微乳...     

A comparative study on the preparation methods and properties of coal-based fluorescent carbon nanoparticles

Fluorescent carbon nanoparticles (FCNPs) have broad application prospects in the fields of bioimaging, ion detection, and photocatalysis. In this paper, coal-based FCNPs were prepared by using mixed acid oxidation, hydrogen peroxide etching, and organic solvent extraction methods (marked as FCNPs-AO, FCNPs-HE, and FCNPs-OS, respectively), and the structures and properties of the as-prepared products were compared. It was found that the coal-based FCNPs obtained by three kinds of methods are all aromatic structural nanomaterials linked with oxygen-containing groups. Among them, FCNPs-AO is a kind of hollow annular spherical particles and FCNPs-HE and FCNPs-OS are solid spherical particles. These FCNPs not only have similar fluorescence properties as traditional quantum dots, but also can be photoexcited to generate photogenerated electrons and holes, and it can also suppress the recombination of photogenerated electrons and holes by using its own surface defects. In particular, the electron transport capability of the FCNPs-AO is stronger than that of FCNPs-HE and FCNPs-OS because of its lower charge transfer impedance, so it can be excited to generate more photogenerated electrons and has the best photogenerated carrier separation efficiency.     

多孔纳米羟基磷灰石/聚乙烯醇复合水凝胶的表征

本文通过采用溶盐致孔法,制备了多孔纳米羟基磷灰石／聚乙烯醇复合水凝胶材料。用透射电子显微镜、红外光谱、扫描电子显微镜和图像分析对材料进行了表征。结果表明纳米羟基磷灰石与聚乙烯醇之间有一定键合,并且多孔纳米羟基磷灰石／聚乙烯醇复合水凝胶中大孔呈均匀分布且相互贯通,复合水凝胶的含水率在80％左右。该种多孔复合水凝胶是可用于人工角膜支架,是一种很有开发前景的生物医用材料。     

Thermal behavior of in vitro mineralized anionic collagen matrices

In the present study porcine skin and bovine pericardium were used as a source of type I collagen. Both were submitted to an alkaline treatment and mineralized by the alternate soaking method. Thermal stability and extent of mineralization have been investigated using DSC and TG. After alkaline hydrolysis there is a decrease in thermal stability but mineralization stabilizes collagen structure. Thermogravimetric data have shown that the amount of hydroxyapatite present in bovine pericardium matrix (45%) was greater than on porcine skin matrix (20%). Presence of hydroxyapatite was confirmed by EDX.     

两种医用胶原膜 60Co辐照改性的比较

胶原作为一种新型生物材料,具有无毒,良好的生物相容性,生物可降解性及可吸收性,广泛用于皮肤创伤的治疗、骨缺损的修复、药物缓释的载体、止血敷料、组织工程支架材料等。但胶原在体内降解太快,不能与组织再生速度相匹配。有必要探讨胶原生物材料的改性方法,便于其更好     

Carbon nanotubes/carbon xerogel-nafion electrodes: a comparative study of preparation methods

We report the preparation and electrochemical characterization of carbon nanotubes (CNT)/carbon xerogel-nafion (CXN) electrodes obtained by casting carbon nanotube inks on carbon xerogel-nafion matrixes under terrestrial (g) and enhanced (13?g) gravity. The impregnated electrodes were compared with composites prepared by mixing CXN dispersions with CNT inks. For casted CNT, alternate current scanning electrochemical microscopy studies along the film-electrode area showed differences that can be correlated with the position of the electronic conducting CNT phase on the more resistive matrix. It revealed the transition from a conductive to dielectric surface when impregnation takes place at terrestrial and enhanced gravity, respectively. Although the addition of CNT enhances the capacitance and mechanical properties of CXN in all preparation methods, the largest specific capacitance was observed in electrodes impregnated at 1?g. Electrodes prepared by mixing and those casted at 13?g show similar capacitance values regardless of contrasting conductivity. A mechanism explaining the microstructural, electrical, and adsorptive differences brought out by the various preparation methods is proposed.     

电化学共沉积HA/胶原复合涂层及其生物性能初探

应用电化学恒电流共沉积法在医用纯钛基底上制备羟基磷灰石(HA)/胶原(collagen)复合涂层.SEM和XPS等测试表明:复合涂层呈特定有序的纳-微米二级多孔结构,化学组分为HA和胶原的有机-无机复合.借助体外细胞的培养实验观察种植于不同材料表面的细胞贴壁及生长形态,显示电化学共沉积的复合涂层具有比纯HA或纯钛表面更好的生物相容性.