组织工程章第2节 生物医用复合材料.docx

第3章3.3 医用高分子复合材料Biomedical Polymer-BasedComposites主要内容..4简介（复合材料vs.生物复合材料）为什么要用生物复合材料复合材料的组成材料生物复合材料的应用213.3.1简介（复合材料vs.生物复合材料）定义与特性l 复合材料是指两种以上不同化学性质或不同物理结构的物质，以微观或宏观形式组合而成的一类新材料。该定义强调和包含了不同种类物质的复合以及同种物质不同结构的复合： 碳纤维增强聚乳酸复合材料、羟基磷灰石与胶原的复合为不同类物质的复合 碳纤维增强碳、羟基磷灰石纤维增强羟基磷灰石陶瓷为同类物质不同结构的复合l 复合材料的显著特性是： 组分性能上的互补性:复合材料不仅兼具组分材料的性质，而且具有单一组分所没有的优良性能, 即1+12 效应。 可设计性 : 利用各组分的比例、分布以及形态改变复合材料的性能。复合材料组分的性质、含量、分布及组成物间的相互作用对复合材料的性质有很大的影响。3l 复合材料的其他性能特点： 高比强度和比模量 如CF/Epoxy复合材料的比强度比钢高3倍以上，比模量比钢高35倍； 抗疲劳性能好 由于增强材料与基体界面可使裂纹变钝，能够阻止疲劳裂纹扩展并改变裂纹扩展方向，因此纤维复合材料有较高的疲劳极限。如金属材料的疲劳极限为抗拉强度的4050%，而碳纤维复合材料可达70-80%。 减震性好 主要是由于：一是比模量高可以较大程度的避免产生共振；二是增强体与基体界面有吸收振动能量的作用，可使产生的振动很快衰减。 其他性能 较好的耐腐蚀性、耐磨性等42复合材料的应用领域 The usage of fibrous composite materials has been increasing involume and applications. Initially, fibrous composites found application in weight critical andhigh performance aero-space components. Later, the domain enlarged to infrastructure, sports, energyapplications with additional requirements like environmental stability,moldability, damage resistance, etc. Today, with biocompatible fibers and matrix systems, fibrouscomposites are finding application as biomaterials. A number offibrous composite implants and devices for orthopedic and dentalapplications have been developed recently .563复合材料三要素p The Reinforcing phase （增强相） Reinforcement usually has much greater mechanicalproperties and serves as the principal load-carryingmembers. Reinforcing effect determined by interface , aspect ratio,distribution, orientation, etc.p The matrix （基体相） Plays a role of a binder to keep the fibers in a desiredlocation and orientation. Transfers load to the fiber through the fiber-matrixinterface . Protects fiber from environmental damage.p The fiber-matrix interface （界面） plays a decided role onthe transformation7l 复合材料界面是指复合材料中增强体与基体接触所构成的一层具有一定厚度（纳米以上）、结构随基体和增强体而异、与基体有明显差别的新相界面相(或称界面层)。因为增强体和基体互相接触时，在一定条件影响下，可能发生化学反应或物理化学反应，如两相间元素的互相扩散、溶解，从而产生不同于原来两相的新相；即使不发生反应、扩散、溶解，也会由于基体的固化、凝固所产生的内应力，或者由于组织结构的诱导效应，导致接近增强体的基体发生结构上的变化或堆砌密度上的变化，导致这个局部基体的性能不同于基体的本体性能，形成界面相。正是界面相的结构与性能对复合材料的整体性能产生影响。l 复合材料移植失败在很多情况下与增强体与基体之间的界面出现问题有关；由于复合材料由两种或两种以上的材料组成，移植失败将会使纤维或颗粒暴露在周边的生物环境中，带来生物相容性问题。84复合材料分类复合材料纤维增强复合材料颗粒增强复合材料9生物（医用）复合材料的定义与分类l 生物医用复合材料是用于对人体的组织、器官或功能进行诊断、治疗、增强或替换的由两种或两种以上不同材料复合而成的一类生物医用材料。l 按功能分，可分为结构复合材料和功能复合材料 结构复合材料的典型结构特征为纤维作为增强相，另一类物质作为基体相，材料的力学性能如强度主要取决于增强材料的用量、排布方式、与基体材料界面的结合等。 功能复合材料主要是赋予原有材料特殊功能，一般原材料作为主相，是结构的主要组成部分，保障材料具有一定的力学性能，而另一相赋予材料特殊的功能，如钛合金基体材料保证力学强度，而涂层羟基磷灰石赋予材料生物相容性。 利用生物技术，将活体组织、细胞、生长因子或药物引入有关生物医用材料以改善生物学性能和功能性，已成为一类新型的生物医用功能复合材料。l 按基体材料分，有金属基复合材料、陶瓷基复合材料、和聚合物基复合材料105A biocomposite is a material formed by a matrix (resin) and areinforcement of natural fibers (usually derived from plants or cellulose).With wide-ranging uses from environment-friendly biodegradablecomposites to biomedical composites for drug/gene delivery, tissueengineering applications and cosmetic orthodontics. They often mimic thestructures of the living materials involved in the process in addition to thestrengthening properties of the matrix that was used but still providingbiocompatibility, e.g. in creating scaffolds in bone tissue engineering.Those markets are significantly rising, mainly because of the increase inoil price, and recycling and environment necessities.- From Wikipedia, the free encyclopediaRefers to composites that can be employed in biomedical engineering,which is the application of concepts and methods of the physicalsciences and mathematics in an engineering approach towards solvingproblems in repair and reconstructions of lost, damaged or deceasedtissues.- S Ramakrishna in An Introduction to Biocomposites11Green/Eco- compositesSubstitute ofBiocompositespetroleum-based materialsBiomedicalEnergy /EnvironmentBio-compatibilityHealthcareBiomedical compositesComposites126聚合物基生物医用复合材料的分类（非活性）不可吸收部分可吸收完全可吸收Non - resorbablePartially - resorbable Fully - resorbableAlumina/PMMABioglass/PSBioglass/PUBone/PMMACF/CCF/EpoxyCF/NylonCF/PBTCF/PEEKCF/PPCF/PTFECF/UHMWPEGF/bis-GMAGF/PMMAGF/PPGF/PUHA/HDPEHA/UHMWPEKF/PCKF/PMAPE/PMMAPET/PUPMMA/PMMAPTFE/PUSilica/bis-GMASilica/SRUHMWPE/bis-GMAUHMWPE/UHMWPECF/PGACF/PLACF/PLLAHA/AlginateHA/PBTHA/PEG-PHBHA/PLAPET/CollagenPET/PHEMAPU/PU-PELAPGA/PGAPLA-PGA/PLAPLLA/PLDLLACF: carbon fibers, C: carbon, GF: glass fibers, KF: kevlarfibers, PMMA: polymethylmethacrylate, PS: polysulfone, PP:polypropylene, UHMWPE: ultra-high-molecular weightpolyethylene, PLDLA: poly(L-DL-lactide), PLLA: poly (L-lacticacid), PGA: polglycolic acid, PC: polycarbonate, PEEK:polyetheretherketone; HA: hydroxyapatite, PMA:polymethylacrylate, BIS-GMA: bis-phenol A glycidylmethacrylate, PU: polyurethane, PTFE: polytetrafluoroethylene,PET: polyethyleneterephthalate, PEA: poltethylacrylate, SR:silicone rubber, PELA: Block co-polymer of lactic acid andpolyethylene glycol, LCP: liquid crystalline polymer, PHB:polyhydroxybutyrate, PEG: polyethyleneglycol, PHEMA:poly(20hydroxyethyl methacrylate)133.3.2 为什么要用生物复合材料l 均质各向同性材料 (如生物医用高分子、金属、陶瓷)在应用中各有优势和不足 For load bearing applications, polymers tend to be tooflexible and too week to meet the mechanical demands ofcertain applications. Metals: high stiffness compared to host tissues as well astheir tendency to create severe imaging artifacts in themost advanced diagnostic 3-D imaging procedures i.e. X-ray Computer Tomography (CT) and nuclear MagneticResonance Imaging (MRI). Ceramics: brittleness, low fracture strength, difficulty infabrication, low mechanical reliability and lack of resilience.147聚合物、陶瓷、金属及生物质材料的拉伸力学性能区间l Metals and ceramics are stiffer, and of larger strength than biological hard tissue.l Polymers are mostly more compliant (lower modulus) than hard tissue and can have strengthsof the same order of magnitude with hard tissue.l Biological tissues show larger spectra of mechanical properties than the other materials. 利用材料性质差异，采用复合工艺制成复合材料以实现性能上的优势互补，能够获得与生物质材料相近的性质，可以有效解决单一材料的强度、韧性及生物相容性等问题。15Composites Science and Technology 64 (2004) 789817生物力学相容性(以骨修复用材料为例)u Refers to the mechanical properties of the implantmaterial, such as elastic modulus (or E, Youngsmodulus) and deformation characteristics, andoptimal load transmission (minimum interfacialstrain mismatch) at the implant/tissue interface.u 生物医学材料和所处部位的生物组织的弹性形变相匹配的性质。植入体在体内所承受的应力，通过材料-组织界面进行传递，如果两者在应力作用下发生的弹性形变不匹配，将使植入体松动而导致植入失败。另外，力学相容性还决定于组织-界面的性质和所承受的负荷的大小。168松质骨Cancellous bone(spongy bone)骨髓密质骨Cortical bone(compact bone)17釉质牙质关节软骨纤维软骨动脉组织眼内晶状体189汞合金Elastic moduli of metals and ceramics are at least 10-20 times higherthan those of hard tissues!192010正常骨密度骨密度正常骨的密度骨密度 polymers, ceramicsLimitations: Discoloration &poor mechanical propertiesBiocomposites : Aesthetic andmechanically performing devices4020SimpliClear:Virtually Invisible Throughout Treatment/41Current materials in orthodontic applications are mainly metals such as stainless steel.In order to improve the appearance and thus patient acceptance, composite arch wireusing advanced composite technology is being developed. Pultrusion techniques areused to produce the elastic arch wire with 50% glass fibres . The outer polymericmaterial can be tailored to match the colour of the teeth.(a)3M polycrystalline alumina bracket with (a) stainless steel (b)developed composite wire made by a pulltrusion process with50% glass fibers(b)42Courtesy of Prof. Teoh SH National University of Singapore21Development of Composite BracketsGlass Braid