纳米羟基磷灰石/聚合物复合骨修复材料

寻找理想的骨修复材料一直是骨科材料领域研究热点。自然骨是由纳米羟基磷灰石和胶原构成的纳米复合材料。源于仿天然硬组织构想的纳米磷灰石-有机高分子复合材料是把高韧性的高分子基质与高刚性的纳米无机磷灰石晶体巧妙结合,使其最大程度地实现两种成分的优势互补和协同优化,赋予仿生纳米复合材料高强韧的力学性能。与组成同样重要的是结构因素,这种材料包括不同尺寸的架构组织和可控取向。纳米羟基磷灰石/高分子复合材料已成为骨组织修复材料领域的研究热点和发展方向。本文综述了近些年用于人体骨组织修复材料的纳米羟基磷灰石/天然(或非天然)高分子材料的制备技术、性能等方面研究进展及现状,并对其发展提出了展望。     

天然高分子复合羟基磷灰石材料的制备与应用

羟基磷灰石(HA)是人类与动物骨骼中主要无机物组成成分,因其具有良好的生物相容性、生物活性和骨传导作用,作为新型合成生物材料已应用于骨组织的修复与替代技术。本文在介绍HA主要制备方法(如:沉淀法、乳液法、水热反应法、溶胶-凝胶法、机械化学法、固态合成法、水解法、超声化学法、热解法、模板法和电沉积法等)和应用的基础上,重点综述了各类天然高分子与HA复合材料的制备及应用研究进展。天然高分子,如:纤维素、淀粉、甲壳素、壳聚糖、蛋白(包括胶原蛋白、明胶、角蛋白、丝蛋白和植物蛋白)等,与HA复合后制备的天然高分子复合羟基磷灰石材料,在保持其生物相容性的同时,又能改善复合材料的机械性能与生物活性,使其可用于医用材料、载体材料和吸附分离材料。最后,本文指出为了满足生物体内的特殊环境(如强的韧性、与骨生长速度匹配性能等)及不同领域的要求,天然高分子复合HA材料需要发展的方向。     

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。     

原位复合法制备层状结构的壳聚糖/羟基磷灰石纳米材料

用原位复合法制备了高性能的壳聚糖/羟基磷灰石(CS/HA)纳米复合材料.用预先沉积的壳聚糖膜将含有羟基磷灰石前驱体的壳聚糖溶液与凝固液隔离,同时控制壳聚糖沉积与羟基磷灰石前驱体转化为羟基磷灰石的过程,使其缓慢且有序地进行.当pH值改变时,质子化的壳聚糖分子链在负电层诱导下有序沉积并形成层状结构与羟基磷灰石原位生成CS/HA,并实现二者分子级复合.XRD和TEM测试证实原位生成的磷酸盐是羟基磷灰石,且其颗粒长约为100nm,宽30～50nm.SEM结果表明,用原位复合法制备的材料具有层状结构,CS/HA(质量比100/5)纳米复合材料弯曲强度高达86MPa,比松质骨的高3～4倍,相当于密质骨的1/2,有望用于可承重部位的组织修复材料.     

庆大霉素对羟基磷灰石/壳聚糖复合材料性能的影响

羟基磷灰石/壳聚糖-庆大霉素(HA/CS-G)缓释材料为骨髓炎的定点缓释给药提供了一种有效的局部药物缓释体系。为了研究抗生素对羟基磷灰石/壳聚糖材料性能的影响,采用共沉淀法制备了HA/CS-G缓释材料。利用红外光谱(IR)、X射线衍射(XRD)和扫描电子显微镜(SEM)对材料进行了表征。以不载药的羟基磷灰石/壳聚糖(HA/CS)为对照,研究了庆大霉素对HA/CS复合材料抑菌性能、力学性能和降解性能等的影响。实验结果表明,HA/CS-G有良好的抑菌效果。负载庆大霉素后HA/CS的机械强度明显增强,而材料的降解速率有所下降。本文采用的二次成型技术显著增大了材料的机械强度。     

羟基磷灰石/胶原矿化机理的研究进展

仿生合成的羟基磷灰石(HAp)/胶原复合材料的结构和成分与天然骨相似,具有很好的生物相容性、生物活性和生物可降解性,有望成为新一代的骨替代材料。羟基磷灰石/胶原矿化过程其实质是晶体在自组装的胶原纤维上形成的过程,但这一过程在体内是如何进行的至今仍然不清楚。对胶原矿化机理的研究能为制备具有更优越结构和功能的新型骨替代材料提供理论参考。本文概述了羟基磷灰石/胶原矿化机理的研究进展。     

PHBV/HA骨修复材料的研究

利用硝酸钙与磷酸钠的水溶液制备羟基磷灰石(HA)，同时在HA生成过程中与聚羟基丁酸一戊酸酯(PHBV)复合，探索了HA增强PHBV使之适于作为骨修复材料的一种新途径。结果表明，HA的均匀分散增进了复合材料中两相问的相互结合，能明显地提高复合材料的力学性能。     

乳酸基聚氨酯与羟基磷灰石的共价杂化

由乳酸聚乙二醇酯二醇中间体（LPEG）、羟基磷灰石以及甲苯-2,4-二异氰酸酯（TDI）发生加聚反应,探讨羟基磷灰石与乳酸基聚氨酯的共价杂化。 对提纯后的杂化产物(HA-g-LPEU5K)及相应共混体系(HA/LPEU5K)的结构及其热稳定性进行了分析对比,HA-g-LPEU5K和HA/LPEU5K热解的剩余百分数分别为92.5%和41.7%。 共价和物理杂化物静置3 d后,分别呈均相、出现少量HA沉淀。 杂化体系的稳定性明显高于共混物,说明乳酸基聚氨酯与羟基磷灰石通过共价键结合而实现了共价杂化。 此外,杂化体系呈现可降解性。     

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...     

碳纳米管对羟基磷灰石基复合材料力学性能的影响

将力学性能优良的碳纳米管(CNTs)与羟基磷灰石(HA)生物陶瓷相复合,发展CNTs/HA复合材料来应用于骨组织修复领域,有望解决HA生物陶瓷力学性能的不足.通过3种不同的制备方法,即通过表面活性剂将CNTs分散在HA基体中、通过酸碱中和反应将CNTs与HA共沉淀以及通过体外浸泡在CNTs上矿化生长HA等方法来获得CNTs/HA复合材料.深入研究CNTs的表面结构和分散状态对CNTs/HA复合材料力学性能的影响.结果表明,CNTs的添加改变了HA的脆性,导致复合材料抗压力学性能得到提高.但是,由于复合材料制备方法的不同,导致CNTs在HA基体中的分散状态、表面结构的完整性以及与HA的界面结合情况不同,导致其抗压力学性能不同.其中,通过表面活性剂将CNTs分散在HA基体中而获得复合材料的抗压力学性能表现最好,而CNTs与HA通过共沉淀法所获得复合材料的抗压力学性能表现最差.     

Hydroxyapatite/polyurethane composites as promising biomaterials

The biomaterials are intended to augment or replace the function of tissues or organs in human body. Every year millions of people require soft- or hard-tissue regeneration worldwide. Polymers and their composites are a large class of biomaterials appreciated for tissue regeneration. Polyurethane (PUR) is an organic synthetic multifunctional polymer with established biomedical applications. The hydroxyapatite (HA) is one of the biocompatible ceramic materials similar to natural bone material. The amalgamation of hydroxyapatite with polyurethane enhances the bioactivity of final product along with the combination of individual properties. Here, we review the synthesis, characterization, and applications studies of HA/PUR-based biomaterials. We initiate this review with a brief and representative compilation of the chemical composition and methods of preparation for HA/PUR biomaterials. Then, moving ahead, first, we review the simple HA/PUR biomaterials and use of PUR templates. Second, we review the significance of modified HA and PUR in these biomaterials. Third, we discuss the potential of bio-based PUR and inclusion of third constituent in the HA/PUR biomaterials. Then, we appraise the involvement of trace nutrient in deposition of HA on PUR scaffolds. Finally, we consider the other expedient applications of HA/PUR composites such as drug delivery system and sorbent of pollutants.     

电纺丝法制备聚乳酸/多壁碳纳米管/羟基磷灰石杂化纳米纤维的研究

电纺丝是一种利用聚合物溶液或熔体在强电场中进行喷射纺丝的加工技术,所制得的纤维、直径一般在数十纳米至几微米之间,比传统方法制得的纤维直径小几个数量级,是获得纳米尺寸长纤维的有效方法之一．     

纳米羟基磷灰石表面接枝聚合左旋丙交酯

为了改善HA纳米粒子与有机PLGA的相容性,分别采用六亚甲基二异氰酸酯加乙二醇、左旋乳酸改性纳米粒子表面后或直接原位接枝聚合左旋丙交酯等3种不同方法,制备了表面修饰聚乳酸的纳米羟基磷灰石(PLLA-g-HA).FTIR、XPS、TEM、TGA测试表明PLLA成功接枝到HA的表面.其中六亚甲基二异氰酸酯加乙二醇改性HA纳米粒子所获得的PLLA接枝率远高于其它两种方法达25%,调整有机相和无机相的比例对PLLA接枝率的影响较小,其在氯仿中可以稳定分散2天以上.共混电纺丝后的拉伸测试表明PLLA-g-HA/PLAG复合纤维膜的力学性能高于HA/PLGA膜,当两者之间的比例为5%拉伸性能达到最大值.     

碳纳米管对羟基磷灰石基复合材料力学性能的影响

将力学性能优良的碳纳米管(CNTs)与羟基磷灰石(HA)生物陶瓷相复合,发展CNTs/HA复合材料来应用于骨组织修复领域,有望解决HA生物陶瓷力学性能的不足。通过3种不同的制备方法,即通过表面活性剂将CNTs分散在HA基体中、通过酸碱中和反应将CNTs与HA共沉淀以及通过体外浸泡在CNTs上矿化生长HA等方法来获得CNTs/HA复合材料。深入研究CNTs的表面结构和分散状态对CNTs/HA复合材料力学性能的影响。结果表明,CNTs的添加改变了HA的脆性,导致复合材料抗压力学性能得到提高。但是,由于复合材料制备方法的不同,导致CNTs在HA基体中的分散状态、表面结构的完整性以及与HA的界面结合情况不同,导致其抗压力学性能不同。其中,通过表面活性剂将CNTs分散在HA基体中而获得复合材料的抗压力学性能表现最好,而CNTs与HA通过共沉淀法所获得复合材料的抗压力学性能表现最差。     

原位沉析法制备磁性氧化铁羟基磷灰石/壳聚糖棒材

首先通过化学沉淀法制备磁性氧化铁羟基磷灰石(Fe3O4/HA),然后以壳聚糖(CS)为基体,利用原位沉析法将Fe3O4/HA与CS复合,制得磁性Fe3O4/HA/CS复合材料.经XRD、粒径分布和PPMS测试,结果表明了Fe3O4/HA复合物的生成.系统研究了磁性Fe3O4/HA/CS棒材力学性能的影响因素,最终确定Fe3O4与HA质量比为3∶17,磁性Fe3O4/HA与CS质量比为9∶91时,棒材的力学性能最优,弯曲强度可达到87.0 MPa,弯曲模量1.57 GPa.     

Associates of thioalkyl derivatives of 2-arylaminopyrimidine with hydroxyapatite-based nanocomposites

Co-precipitation and ultrasonic treatment methods have been used for the in situ formation of the composites of hydroxyapatite (HA) covered with nanoparticles of magnetite as well as compositions of magnetite, gold and silver. The thioalkyl-substituted derivatives of 2-arylaminopyrimidine, structural analogs of antitumor drug Imatinib containing one or two SH groups and capable to chemisorption on hydroxyapatite and its nanocomposites, have been synthesized. Two-component Fe₃O₄(HA) and three-component Fe₃O₄(HA)Au and Fe₃O₄(HA)Ag composites have been found the most promising as nanocarriers of bioactive compounds.     

Water dispersible hydroxyapatite nanoparticles functionalized by a family of aminoalkyl phosphates

A series of aminoalkyl phosphates (AAP-n, with carbon number n ranging from 2 to 6) are used as surface modifiers to prepare hydroxyapatite hydrocolloids. The resulting nanoparticles (Cn-HA) possess a coreshell structure where an ionized layer of calcium-(AAP-n) complex [⁺H₃N-(CH₂)_n-OPO₃Ca] encapsulates each hydroxyapatite core. Long-term colloidal stability is achieved due to the electrostatic repulsion among the suspending particles. The incorporation of AAP-n results in a preferential crystal growth along c-axis, showing an increasing aspect ratio of particles from C2-HA to C6-HA. Preliminary cell culture using osteoblast-like MG63 cells shows no cytotoxicity associated with the as-prepared Cn-HA particles. The functional amino groups around the nanoparticles could be used to graft various organic chains to prepare homogeneous HA/polymer composites as bone grafting materials.     

Viscoelastic properties of poly(ε‐caprolactone) – hydroxyapatite micro‐ and nano‐composites

Various composites have been proposed in the literature for the fabrication of bioscaffolds for bone tissue engineering. These materials include poly(ε‐caprolactone) (PCL) with hydroxyapatite (HA). Since the biomaterial acts as the medium that transfers mechanical signals from the body to the cells, the fundamental properties of the biomaterials should be characterized. Furthermore, in order to control the processing of these materials into scaffolds, the characterization of the fundamental properties is also necessary. In this study, the physical, thermal, mechanical, and viscoelastic properties of the PCL‐HA micro‐ and nano‐composites were characterized. Although the addition of filler particles increased the compressive modulus by up to 450%, the thermal and viscoelastic properties were unaffected. Furthermore, although the presence of water plasticized the polymer, the viscoelastic behavior was only minimally affected. Testing the composites under various conditions showed that the addition of HA can strengthen PCL without changing its viscoelastic response. The results found in this study can be used to further understand and approximate the time‐dependent behavior of scaffolds for bone tissue engineering. Copyright © 2012 John Wiley & Sons, Ltd.     

Surface‐modified hydroxyapatite linked by L‐lactic acid oligomer in the absence of catalyst

A new surface modification method of hydroxyapatite nanoparticles (n‐HA) by surface grafting reaction of L ‐lactic acid oligomer with carboxyl terminal (LAc oligomer) in the absence of any catalyst was developed. The LAc oligomer with a certain molecular weight was directly synthesized by condensation of L ‐lactic acid. Surface‐modified HA nanoparticles (p‐HA) were attested by Fourier transformation infrared spectroscopy, ³¹P MAS‐NMR, and thermal gravimetric analysis (TGA). The results showed that LAc oligomer could be grafted onto the n‐HA surface by forming a Ca carboxylate bond. The grafting amount of LAc oligomer was about 13.3 wt %. The p‐HA/PLLA composites showed good mechanical properties and uniform microstructure. The tensile strength and modulus of the p‐HA/PLLA composite containing 15 wt % of p‐HA were 68.7 MPa and 2.1 GPa, respectively, while those of the n‐HA/PLLA composites were 43 MPa and 1.6 GPa, respectively. The p‐HA/PLLA composites had better thermal stability than n‐HA/PLLA composites and neat PLLA had, as determined by isothermal TGA. The hydrolytic degradation behavior of the composites in phosphate buffered saline (PBS, pH 7.4) was investigated. The p‐HA/PLLA composites lost their mechanical properties more slowly than did n‐HA/PLLA composites in PBS because of their reinforced adhesion between the HA filler and PLLA matrix. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5177–5185, 2005