超顺磁性羟基磷灰石/壳聚糖棒材的制备

以壳聚糖膜为模板将磁性羟基磷灰石前驱体的壳聚糖醋酸溶液与NaOH凝固液隔离，OH^-向磁性羟基磷灰石前驱体的壳聚糖醋酸溶液内部的渗透引起pH值变化，导致质子化的壳聚糖在模板上沉积的同时无机物就地生成，原位复合制备出无机纳米颗粒分散均匀的磁性羟基磷灰石／壳聚糖（HA／CS）复合棒材．生成的超顺磁性四氧化三铁和羟基磷灰石颗粒大小均一（大约长30nm，宽20nm），在基质中分布均匀、没有出现明显的团聚现象．     

纳米羟基磷灰石/壳聚糖复合生物材料研究

骨的特殊性能决定了其在人体中起重要的功能作用,人工骨材料对骨缺损的治疗有重要意义。羟基磷灰石是人和动物骨骼的主要无机成分;壳聚糖是天然可降解多糖,降解产物为对人体组织无毒、无害的氨基葡萄糖。纳米羟基磷灰石/壳聚糖复合生物材料可以实现羟基磷灰石和壳聚糖两者的优势互补,具有优良的生物活性、生物相容性和力学性能。介绍了近年来纳米羟基磷灰石/壳聚糖复合生物材料的主要合成方法(如共混法、共沉淀法、原位沉析法、交替沉积法和模拟体液法等),并在此基础上介绍了基于纳米羟基磷灰石/壳聚糖的三元复合材料的研究及发展情况;最后,展望了纳米羟基磷灰石/壳聚糖复合生物材料未来的发展方向。     

原位增强羟基磷灰石/壳聚糖复合棒材

利用低温水溶液均相沉积法制备了磷酸钙盐微纤维;应用原位沉析法制备了壳聚糖(CS)三维棒材及羟基磷灰石(HA*)/CS复合棒材.XRD证实应用原位沉析法制备HA*/CS复合棒材过程中,磷酸钙盐转化为羟基磷灰石结构,尺寸为10～60 μm,并用SEM对晶体形貌进行了表征,分析了转化机制.HA*/CS复合材料的微观形貌表明,...     

羟基磷灰石/胶原蛋白/壳聚糖多孔支架的制备及性能研究

通过共滴定法合成工艺制备出羟基磷灰石/胶原蛋白粉体,以制备的羟基磷灰石/胶原蛋白粉体为原料,选用冷冻干燥成型技术,制备羟基磷灰石/胶原蛋白/壳聚糖复合多孔支架材料.研究结果表明:通过X射线衍射分析和透射电镜分析,羟基磷灰石/胶原蛋白纳米粉体中羟基磷灰石晶粒是针状的弱结晶的晶体,与天然骨中的纳米羟基磷灰石晶粒相近;羟基磷灰石/胶原蛋白/壳聚糖复合多孔支架的抗压强度、孔隙率、平均孔径可达到骨组织工程支架材料的要求,是由有机-无机三相复合、具有三维多孔结构、又有良好机械性能的具有发展潜力的骨支架材料.     

碳纳米管/羟基磷灰石生物复合涂层的制备与微观结构研究

采用电泳沉积的方法在钛板表面制备了碳纳米管/羟基磷灰石复合涂层。XRD研究发现,复合涂层的成分主要是羟基磷灰石和碳纳米管;IR研究发现,复合涂层中含有羟基、磷酸根等官能团;SEM研究发现,复合涂层均匀致密,碳纳米管与羟基磷灰石颗粒混合均匀,且碳纳米管的表面已被1层羟基磷灰石薄膜均匀包覆。随着碳纳米管含量从20%增加到40%,复合涂层的致密度逐渐提高,其表面质量逐渐改善。     

钛表面接枝壳聚糖诱导羟基磷灰石涂层的形成

钛及其合金材料广泛应用于矫形外科植入器械等生物材料领域,在钛表面制备羟基磷灰石涂层可以明显提高其生物相容性及其成骨性能.采用仿生溶液生长法在钛表面及共价接枝壳聚糖的钛表面沉积羟基磷灰石涂层,结果表明,与没有接枝壳聚糖的钛相比,在钛表面接枝壳聚糖可以加速诱导羟基磷灰石涂层的形成,且形成的涂层致密均匀.     

纳米羟基磷灰石/壳聚糖复合骨修复材料的共沉淀法制备及其性能表征

通过共沉淀法制备了纳米羟基磷灰石/壳聚糖复合骨修复材料,并采用 TEM、IR、XRD、TGA 及万能材料试验机等手段对材料进行分析表征,还通过对材料的燃烧试验研究了复合材料中两相间的分散均匀性。结果表明:复合材料中的羟基磷灰石为类似于自然骨矿物相的弱结晶含碳酸纳米晶体,并均匀分散于有机相壳聚糖中;复合后壳聚糖在 1655cm-1的酰胺Ⅰ谱带和 1599cm-1 的—NH2 吸收峰均向低波数方向移动,暗示复合材料中两相间发生了相互作用。复合材料的力学性能较之两种单组分材料有明显的改善,当纳米羟基磷灰石/壳聚糖重量比为 70/30 时,复合材料的抗压强度最高,达120MPa左右,可满足骨组织修复与替代材料的要求。     

聚丙烯包装薄膜表面沉积羟基磷灰石改性研究

羟基磷灰石具有稳定的结构,常用作人工骨质材料,在包装塑料薄膜表面沉积羟基磷灰石是一种新的尝试.采用交替沉积法在聚丙烯薄膜表面沉积羟基磷灰石.扫描电镜照片显示羟基磷灰石均匀地分布在薄膜表面;接触角测试结果显示,薄膜表面接触角从99.8°降低到60.3°;透氧性能测试显示,氧气渗透系数为原薄膜的一半.这些结果表明,聚丙烯包装薄膜表面沉积羟基磷灰石能有效地提高其亲水性能和阻隔性能.     

纳米羟基磷灰石/壳聚糖/羧甲基纤维素三元复合骨修复材料的制备和性能研究

用溶液共混法在常温常压下制备了不同比例的纳米羟基磷灰石/壳聚糖/羧甲基纤维素三元复合骨修复材料.用燃烧实验、IR、XRD、SEM及TEM对复合材料的组成结构及形貌进行了分析和观察,并初步研究了其力学性能.结果表明该复合材料中纳米羟基磷灰石均匀分散在壳聚糖和羧甲基纤维素网络结构中,三组分间还产生了一定的相互作用,其形态、尺寸及结构与自然骨类似,且其抗压强度比纳米羟基磷灰石/壳聚糖二元复合材料更高;同时,通过调节各组分比例,可制得不同抗压强度的复合材料.因此,该三元复合材料可望作为一种新型可降解的非承重部位骨修复材料,在生物医学材料的研究中具有重要意义.     

胆固醇/卵磷脂对壳聚糖模板中羟基磷灰石微结构的影响

以壳聚糖、羟基磷灰石为基材制备了胆固醇/卯磷脂/壳聚糖/羟基磷灰石（Chol/PC/CS/HA）复合材料,研究了胆固醇与卯磷脂的协同作用对壳聚糖模板中羟基磷灰石显微结构的影响。结果表明：随着不同比例胆固醇与卯磷脂的加入,羟基磷灰石的形貌由球状向棒状转变,当卯磷脂与胆固醇的比例为5：1时复合材料体系中羟基磷灰石的显微形貌...     

反应pH值对原位水热沉积法制备纳米羟基磷灰石/壳聚糖复合材料的影响

为避免羟基磷灰石(HA)在壳聚糖(CS)基体中分子出现分布不均的现象，在结合原位沉析法和水热法二者优点的基础上，发展了原位水热沉析法来制备HA/CS复合材料，并深入研究不同的反应pH值对该复合材料的影响。研究表明，在不同反应pH值下制备的复合材料，均由CS晶体和低结晶度的纳米HA晶体所组成，2种晶体均出现沿c轴方向上的择优生长。随着反应pH值的增大，复合材料中HA和CS分子的结晶度均增大，HA晶体尺寸增大，CS分子排列有序化程度增高，且二者之间发生较强的化学键合作用。当反应pH值增大到12时，复合材料中纳米HA的晶体尺寸约为27.63 nm，且均匀地分布在CS分子中；CS分子为高结晶度的α晶型，且分子排列规整,有序化程度高;存在于HA与CS分子间的化学键合作用最强。     

Preparation and characterization of nano-hydroxyapatite within chitosan matrix

Nano-composites that show some features of natural bone both in composition and in microstructure have been prepared by in situ precipitation method. Apatite phase has been prepared from cost-effective precursors (calcite and urea phosphate) within chitosan (CS) matrix dissolved in aqueous acetic acid solution. The compositional and morphological properties of composites were studied by means of Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Depending on the reaction conditions (temperature, reaction time, glucose addition and pH control) in addition to hydroxyapatite (HA) as a major phase, octacalcium hydrogen phosphate pentahydrate (OCP) and dicalcium phosphate anhydrate (DCPD) were formed as shown by XRD and FTIR. Crystallite lengths of precipitated HA estimated by Scherrer's equation were between 20 and 30 nm. A fibrous morphology (~ 400 nm) of HA observed by TEM indicates that HA nucleates on chitosan chains.     

Design of novel polysaccharidic nanostructures for gene delivery

The goal of the present work was to develop a new synthetic nanosystem for gene delivery. For this purpose, we chose two polysaccharides, hyaluronic acid (HA) and chitosan (CS), as the main components of the nanocarrier. Nanoparticles with different hyaluronate:chitosan (HA:CS) mass ratios (0.5:1 and 1:1) and different polymer molecular weights (hyaluronate 170 (HA) or <10?kDa (HAO) and chitosan 125 (CS) or 10-12?(CSO)?kDa) could be obtained using an ionic crosslinking method. These nanoparticles were loaded with pDNA and characterized for their size, zeta potential and pDNA association efficiency. Moreover, their toxicity and ability to transfect the model plasmid pEGFP-C1 were evaluated in the cell line HEK 293, as well as their intracellular fate. The results showed that HA:CS nanoparticles have a small size in the range of 110-230?nm, a positive zeta potential of +10 to +32?mV and a very high pDNA association efficiency of 87-99% (w/w). On the other hand, nanoparticles exhibited low cell toxicity and transfection levels up to 25% GFP expressing HEK?293 cells, lasting for the whole observation period of 10 days. We also provide basic information about the role of both polymers, HA and CS, and the effect of their molecular weight on the effectiveness of the resulting DNA nanocarrier, being the highest transfection levels observed with HAO:CSO 1:1 nanoparticles. In?conclusion, HA:CS nanoparticles are promising carriers for gene delivery.     

Chitosan-Based Nanocomposite Scaffolds for Tissue Engineering Applications

This article reports the fabrication of three-dimensional porous chitosan and hydroxyapatite (HA)/chitosan composite scaffolds by the thermally induced phase separation (TIPS) technique, for bone tissue engineering. Different amounts of HA nanoparticles (10%, 20%, and 30% g/g) were added to the chitosan solution to produce HA/chitosan composite scaffolds of varying compositions. The morphology and pore structure of the scaffolds vis-à-vis composition were characterized using scanning electron microscopy (SEM) and an energy dispersive X-ray (EDX). Both pure chitosan and HA/chitosan composite scaffolds were highly porous and had interconnected pores. The pore sizes ranged from several micrometers to a few hundred micrometers. The HA nanoparticles were well dispersed and physically coexisted with chitosan in the composite scaffolds. However, some agglomeration of HA nanoparticles was observed on the surface of pore walls when a relatively large amount of HA was used. The composite 3D scaffolds are very promising for use in bone tissue engineering application.     

Sol-gel原位相转变矿化制备纳米羟基磷灰石/壳聚糖复合支架材料

为了模拟天然骨组织的结构和成分,以羟基磷灰石（HA）为钙磷源,以壳聚糖（CS）为大分子基质材料,在酸性环境中形成均相溶液,通过Sol-gel相转变矿化方法和陈化处理,原位构建了纳米HA/CS复合多孔支架材料,研究了共沉积时体系的pH值和陈化时间对支架压缩强度、晶相组成及形貌等的影响。结果表明体系pH为10和11时,支架...     

Preparation of HA/chitosan composite coatings on alkali treated titanium surfaces through sol-gel techniques

In this paper we demonstrated for the first time the feasibility to generate well crystallized hydroxyapatite/chitosan (HA/CS) composite coatings on alkali treated titanium surfaces through combining the in situ hydrothermal precipitation and sol-gel dip coating technique without introducing any other coupling agent. Alkali treatment converting hydrophobic Ti surfaces into super-hydrophilic surfaces was the pre-requirement of uniform coatings. Preliminary cell culturing results revealed that the coatings were biocompatible and supported osteoblasts attachment.     

Biodegradation and compressive strength of phosphorylated chitosan/chitosan/hydroxyapatite bio-composites

The research about how to obtain an organic/inorganic bio-composite with excellent comprehensive properties is an active research field. Nowadays, very few of the achievements were applied to the clinical use due to many reasons. In this work, the purpose was to get a three-phase composite with good compressive strength by using phosphorylated chitosan. Phosphorylated modification of chitosan would bring new properties such as metal chelating. Four phosphorylated chitosan/chitosan/hydroxyapatite (PCS/CS/HA) composites with the weight ratios of 40/40/20, 30/30/40, 20/20/60, 10/10/80 were prepared through the coprecipitation method. The maximum value of compressive strength was measured about 70.25 MPa corresponding to the PCS/CS/HA composite rod with a weight ratio of 30/30/40. The composite rod maintained 64% of original compressive strength after soaking in simulated body fluid for 20 days. All the results showed that the PCS/CS/HA composite (30/30/40), had a good compressive strength, was appropriate to be used as a novel bio-composite for bone tissue engineering.     

壳聚糖/羟基磷灰石表面修饰聚己内酯多孔骨支架的制备及性能

采用选择性激光烧结技术构建多孔聚己内酯(PCL)骨支架,用原位合成的方法制得壳聚糖/羟基磷灰石(CS/HA)悬浮液,并采用真空浸泡、低速离心和冷冻凝胶的方法使CS/HA黏附在PCL支架的表面,以改善骨支架的生物相容性和细胞增殖活性。通过X射线衍射(XRD)和扫描电子显微镜(SEM)观测复合支架的物相和形貌,测量支架的压缩强度和杨氏模量,测量支架表面的水接触角,并通过体外细胞实验研究复合支架的生物学性能。实验结果表明,原位合成的方法制得了羟基磷灰石(HA);CS/HA凝胶与PCL骨支架表面黏附良好;CS/HA改善了PCL支架表面的亲水性,提升了骨支架的生物相容性和细胞增殖活性。     

电气石/壳聚糖复合纤维的表征及细胞相容性

以壳聚糖为基体,电气石为分散相,采用溶液纺丝法制备电气石/壳聚糖复合纤维,利用光学显微镜、扫描电镜以及红外光谱仪对材料进行表征。电气石/壳聚糖复合纤维与人骨肉瘤细胞株（MG63）体外共培养,初步评价了材料的细胞相容性。结果显示,电气石颗粒在复合纤维中分散均匀且被壳聚糖包裹,纤维表面无裸露电气石。细胞在电气石/壳聚糖复合纤维表面黏附及生长增殖状况良好,材料对细胞无明显毒性。该材料有望成为一种良好的创伤修复敷料。     

钛表面制备羟基磷灰石/壳聚糖复合涂层研究

通过原位水热合成和溶胶-凝胶浸提涂敷法在碱处理的钛表面制备了HA/CS复合涂层.接触角检测表明碱处理使钛表面具有超亲水性. X射线衍射分析表明复合涂层成分为HA和CS,各组分含量由热重分析确定.用扫描电镜对复合涂层的形貌进行观察,发现不同HA含量的复合涂层具有不同的形貌.通过培养成骨细胞考察了复合涂层的细胞相容性. Alamar Blue检测表明HA/CS复合涂层表面细胞粘附及增殖能力较好.ALP检测表明HA/CS复合涂层表面的细胞分化能力较好.综合研究结果表明,复合涂层有较好的细胞相容性.