数字光处理技术成形β-磷酸三钙生物陶瓷及其生物学评价

目的 研究数字光处理技术(Digital Light Processing,DLP)打印β-磷酸三钙(Beta-Tricalcium Phosphaye,β-TCP)生物陶瓷的成形性能与生物学性能。方法 通过表面活性剂硬脂酸改性β-TCP粉体,将改性后的β-TCP粉体与丙烯酸类及甲基丙烯酸类树脂均匀混合成3D打印浆料,进行3D打印性能研究。采用X射线衍射仪(X-Ray Diffraction,XRD)、接触角测量仪、数字式黏度计表征β-TCP粉体、浆料及3D打印支架性能,并进行体外细胞试验研究β-TCP多孔支架的生物学性能。结果 粉体XRD结果显示,硬脂酸改性β-TCP粉体并未影响原始粉体的物相组成;而表面活性剂硬脂酸降低了树脂与粉体表面的接触角,提高了粉体与树脂的亲和性。3D打印β-TCP浆料的固含量为48%(体积分数),在常温下,黏度仅为2.91 Pa.s。支架XRD结果显示,3D打印β-TCP多孔支架的主要物质仍为β-TCP,仅有部分转化为α-TCP。体外细胞试验表明,3D打印β-TCP支架表面可黏附大量细胞,培养7 d后,细胞延伸至支架孔隙内,同时其溶血性结果较钛合金(Ti6Al4V)及聚醚醚酮(PEEK)的优异。结论 3D打印β-TCP多孔支架可作为骨替代植入物,为治疗临床骨缺损疾病提供新途径。     

光固化3D打印磷酸钙基生物陶瓷支架的研究进展

磷酸钙基生物陶瓷多孔支架是临床中实现骨缺损再生修复的常用骨移植物。光固化3D打印技术以其优异的打印精度和复杂结构成形特性能够精确地控制支架孔尺寸、孔形状、孔连通率,在制备生物陶瓷多孔支架领域展现出巨大的应用潜力。然而,利用光固化3D打印技术制备磷酸钙基生物陶瓷多孔支架仍面临亟需克服的挑战,如缺乏性能优异的磷酸钙基陶瓷打印浆料、打印及后处理工艺不成熟、制备的磷酸钙基陶瓷多孔支架的性能还有待提升。本文首先介绍了几种常用的光固化3D打印技术基本原理与特征,然后从3D打印成形工艺、力学性能、生物活性、支架结构及功能化等方面系统探讨了光固化3D打印技术在制备磷酸钙基生物陶瓷多孔支架领域的研究进展及存在的问题,最后展望了光固化3D打印磷酸钙基生物陶瓷多孔支架的发展趋势和突破点,为利用光固化3D打印技术制备成本低、综合性能优异的磷酸钙基生物陶瓷多孔支架提供参考。     

荔枝状CaCO3@HA/Fe3O4磁性介孔多级微球的制备

为了克服常规的生物陶瓷微球缺乏靶向功能的缺点, 本研究制备了内核为CaCO₃, 外壳为磁性可调控羟基磷灰石(HA)的新型荔枝状多孔微球。结果表明: 抗肿瘤药物阿霉素(DOX)能有效地负载于磁性HA微球上, 并具备磁性靶向功能。此外, HA外壳具有良好的生物相容性和pH响应特性, 可在模拟酸性肿瘤细胞环境中控制DOX的释放, 有效杀死肿瘤细胞, 并在模拟正常细胞培养环境中减少对正常细胞的毒副作用。这种新型的微球材料具有超顺磁性能, 且微结构可控, 是一种智能化药物控释微球载体, 可以灵敏地释放DOX, 从而有效地实现抗肿瘤活性。     

粉体粒径对数字光处理3D打印金刚石复合材料性能的影响

基于数字光处理(Digital light processing,DLP) 3D打印技术的成型原理,系统探索了含不同粒径金刚石粉体的金刚石树脂浆料的流变性能、固化特性以及所制备的金刚石-树脂复合材料的力学性能。研究结果表明:增大粉体粒径可以降低颗粒的比表面积与表面能量,有效减小金刚石树脂浆料的粘度,在打印成型过程中有利于提高浆料的流动性;结合Beer-Lambert模型方程可知,在相同的曝光能量下,粉体粒径越大,对应金刚石浆料的固化深度越大,在打印过程中可以提供更高的层间结合强度,但是扩展固化宽度增大,导致成型精度降低。金刚石-树脂复合材料的力学性能测试结果表明增大粉体的粒径对复合材料的邵氏硬度没有显著的影响,但是有利于提高复合材料的抗弯强度和弹性模量。本研究通过光固化3D打印技术制备了含不同粒径金刚石粉体的金刚石-树脂复合材料,可为未来光固化树脂结合剂金刚石工具的成型制备提供实验基础。     

特殊粒径分布球形Ni粉的制备及SLM工艺性能研究

3D打印复杂三维结构的Ni基合金时表面易产生突起而粗糙,难以获得致密的打印组织。基于此,本研究采用低温喷雾干燥与热处理相结合的新方法,制备得到了物相纯净、球形度高、流动性好的具有粒径单峰和双峰分布的两种选区激光熔化(SLM)用球形Ni粉。结果表明:粒径双峰分布的Ni粉具有更大的比表面积和更高的堆积密度以及更高的导热系数;在打印过程中,可以吸收更多的激光能量形成更宽的致密熔道,无球化现象;粒径单峰分布的Ni粉打印件表面有少量球化颗粒和微裂纹生成,硬度和模量随压入深度的增加而逐渐下降;粒径双峰分布的Ni粉打印件的相对密度达到99. 8%,硬度和模量随压入深度的增加而趋于稳定,其塑性较粒径单峰分布Ni粉打印件提高了30%。     

聚乳酸/聚乙二醇/羟基磷灰石多孔骨支架的3D打印制备及其生物相容性

聚乳酸(PLA)是一种应用广泛的生物高分子材料,但在应用过程中存在韧性、亲水性、生物活性差等缺点。用聚乙二醇(PEG)和羟基磷灰石(HA)对PLA进行改性。通过熔融共混制备不同质量比的PLA/PEG/HA复合3D打印线材,并通过分析PLA/PEG/HA线材的力学性能、结晶性能、热性能、流变性能等,筛选更适合熔融沉积成型(FDM)的3D打印成型线材,进而利用3D打印制备精度高的力学性能试样及生物相容性好、细胞可增殖和分化的生物多孔支架。结果表明:PEG的添加提高了PLA的韧性,降低了PLA的熔点。HA的添加则提高PLA/PEG/HA复合材料的弹性模量和冷结晶温度,同时HA也可以改善复合材料的加工性能。SEM与荧光标记结果表明多孔支架与细胞具有良好的生物相容性。生物支架对体外细胞的成功培养,为进一步发掘生物多孔支架在动物体内、生物医学及定制化应用方面提供了潜在可能。     

聚乙烯吡咯烷酮对羟基磷灰石结晶和形貌的影响

采用化学均相沉淀法,在水热条件下以Ca(NO3)2.4H2O和(NH4)2HPO4为原料,合成了具有特殊形貌的羟基磷灰石(HA)微球。在合成过程中加入聚乙烯吡咯烷酮(PVP)为模板剂,研究了PVP的加入和浓度对HA晶体形貌和粒径的影响。结果表明,PVP的加入改变了HA晶体的生长方式,颗粒是由针片状HA晶体组成的微球;HA颗粒的形貌和粒径可以通过调节PVP浓度来控制,当PVP浓度从0%(质量分数,下同)增加到12%时,HA颗粒的形貌逐渐由不规则的絮状团聚物转变为规整的微球,组成微球的结构单元也随PVP浓度的变化有所不同。     

3D打印生物陶瓷用于骨、软骨修复研究获系列进展

正近日,中国科学院上海硅酸盐研究所研究员吴成铁与常江带领的研究团队在3D打印生物陶瓷用于骨、软骨修复研究中取得系列进展。通过3D打印方法制备有序大孔结构的锰-磷酸三钙(Mn-TCP)生物陶瓷支架。研究团队与上海交通大学附属第九人民医院教授蒋欣泉团队合作,制备出了由空心     

3D打印用球形钛粉制备技术研究现状

目前,我国3D打印材料市场规模已达到30亿元,其中钛合金占比最大,达到了20%。3D打印钛合金零件被广泛应用于航空航天、核工业、医疗器械及运动器材等领域。钛合金粉末作为3D打印钛合金零件的重要金属材料,其性能(包括氧含量、纯净度、球形度、粉末粒径、粉体密度等)直接影响到3D打印钛合金零件的成型性能,3D打印钛粉的制备技术及工艺已成为国内外开发和研究的热点。首先详细介绍了制备球形钛粉的主要方法,包括雾化法(气雾化、离心雾化、等离子雾化)、球化法(激光球化、等离子球化)、造粒烧结脱氧法,同时综述了国内外研究现状;接着对球形钛粉制备技术进行了比较,认为造粒烧结法因制粉成本低廉而具有很大的发展前景;最后对球形钛粉制备技术的发展趋势进行了展望。     

胶原/壳聚糖/羟基磷灰石复合微球的制备及表征

首先探讨了实验参数对胶原/壳聚糖复合微球的影响,确定了胶原/壳聚糖的最佳理论质量配比以及戊二醛和氢氧化钠的最佳加入量。随后,在上述最佳条件的基础上,采用分散乳化法制备了具有不同羟基磷灰石(HA)含量的胶原/壳聚糖/HA三组分复合微球。采用傅里叶变换红外光谱(FT-IR)和扫描电子显微镜(SEM)对微球进行了表征,并探讨了HA的含量对微球组成、形态和分散性的影响。结果表明,复合微球的分散性随着HA含量的增加而逐渐提高。当HA含量为30%时,可以获得球形规则、分散性高且粒径分布均匀的复合微球,所得微球的平均粒径约为5μm。然而,当HA含量超过30%时会导致微球的球形呈现不规则的特征。     

Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model

We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500 μm and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, β-tricalcium phosphate (β-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteopontin (OPN) and collagen type I (COL-1). Moreover, the biocompatibility, bone repairing capacity and degradation in three different bone substitute materials were estimated using a critical-size rat calvarial defect model in vivo. The defects were evaluated by micro-computed tomography and histological analysis at four and eight weeks after surgery, respectively. The results showed that each of the studied scaffolds had its own specific merits and drawbacks. Three-dimensional printed PLA/HA scaffolds possessed good biocompatibility and stimulated BMSC cell proliferation and differentiation to osteogenic cells. The outcomes in vivo revealed that 3D printed PLA/HA scaffolds had good osteogenic capability and biodegradation activity with no difference in inflammation reaction. Therefore, 3D printed PLA/HA scaffolds have potential applications in bone tissue engineering and may be used as graft substitutes in reconstructive surgery.     

Static and dynamic cultivation of bone marrow stromal cells on biphasic calcium phosphate scaffolds derived from an indirect rapid prototyping technique

The adequate regeneration of large bone defects is still a major problem in orthopaedic surgery. Synthetic bone substitute materials have to be biocompatible, biodegradable, osteoconductive and processable into macroporous scaffolds tailored to the patient specific defect. Hydroxyapatite (HA) and tricalcium phosphate (TCP) as well as mixtures of both phases, biphasic calcium phosphate ceramics (BCP), meet all these requirements and are considered to be optimal synthetic bone substitute materials. Rapid prototyping (RP) can be applied to manufacture scaffolds, meeting the criteria required to ensure bone ingrowth such as high porosity and defined pore characteristics. Such scaffolds can be used for bone tissue engineering (BTE), a concept based on the cultivation of osteogenic cells on osteoconductive scaffolds. In this study, scaffolds with interconnecting macroporosity were manufactured from HA, TCP and BCP (60 wt% HA) using an indirect rapid prototyping technique involving wax ink-jet printing. ST-2 bone marrow stromal cells (BMSCs) were seeded onto the scaffolds and cultivated for 17 days under either static or dynamic culture conditions and osteogenic stimulation. While cell number within the scaffold pore system decreased in case of static conditions, dynamic cultivation allowed homogeneous cell growth even within deep pores of large (1,440 mm³) scaffolds. Osteogenic cell differentiation was most advanced on BCP scaffolds in both culture systems, while cells cultured under perfusion conditions were generally more differentiated after 17 days. Therefore, scaffolds manufactured from BCP ceramic and seeded with BMSCs using a dynamic culture system are the method of choice 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。     

Electrospun PCL/PLA/HA based nanofibers as scaffold for osteoblast-like cells

Polycaprolactone (PCL), poly (lactic acid) (PLA) and hydroxyapatite (HA) are frequently used as materials for tissue engineering. In this study, PCL/PLA/HA nanofiber mats with different weight ratio were prepared using electrospinning. Their structure and morphology were studied by FTIR and FESEM. FTIR results demonstrated that the HA particles were successfully incorporated into the PCL/PLA nanofibers. The FESEM images showed that the surface of fibers became coarser with the introduction of HA nanoparticles into PCL/PLA system. Furthermore, the addition of HA led to the decreasing of fiber diameter. The average diameters of PCL/PLA/HA nanofiber were in the range of 300-600 nm, while that of PCL/PLA was 776 +/- 15.4 nm. The effect of nanofiber composition on the osteoblast-like MC3T3-E1 cell adhesion and proliferation were investigated as the preliminary biological evaluation of the scaffold. The MC3T3-E1 cell could be attached actively on all the scaffolds. The MTT assay revealed that PCL/PLA/HA scaffold shows significantly higher cell proliferation than PCL/PLA scaffolds. After 15 days of culture, mineral particles on the surface of the cells was appeared on PCL/PLA/HA nanofibers while normal cell spreading morphology on PCL/PLA nanofibers. These results manifested that electrospun PCL/PLA/HA scaffolds could enhance bone regeneration, showing their marvelous prospect as scaffolds for bone tissue engineering.     

Biocompatibility of ceramic scaffolds for bone replacement made by 3D printing

Bone replacement materials used in tissue engineering require a high degree of safety and biological compatibility. For these reasons synthetic bone replacement materials based on calcium‐phosphates are being used more widely. To mimic natural bone, rapid prototyping processes and especially 3D printing are favourable. Using 3D printing, complex 3 dimensional structures can be made easily. In this study we successfully performed biocompatibility tests with a Hydroxyapatite test structure (HA‐S) made by 3D printing. Cytotoxicity tests were carried out according to DIN ISO 10993‐5 in static and dynamic cultivation setups. To estimate cell proliferation and analyze morphology, histological evaluation was done. In summary, good cell viability as well as good proliferation behaviour were found. Moreover, these results show that the 3D printing process in combination with the suitable material presented in this study is well suited for fabricating scaffolds for TE in the required accuracy and biological compatibility.     

In vitro cellular response to hydroxyapatite scaffolds with oriented pore architectures

The objective of the present work was to evaluate the in vitro cellular response to hydroxyapatite (HA) scaffolds with oriented pore architectures. Hydroxyapatite scaffolds with approximately the same porosity (65–70%) but two different oriented microstructures, described as ‘columnar’ (pore diameter = 90–110 μm) and ‘lamellar’ (pore width = 20–30 μm), were prepared by unidirectional freezing of suspensions. The response of murine MLO-A5 cells, an osteogenic cell line, to these scaffolds was evaluated using assays of MTT hydrolysis, alkaline phosphatase (ALP) activity, and alizarin red staining. While the cellular response to both groups of scaffolds was better than control wells, the columnar scaffolds with the larger pore width provided the most favorable substrate for cell proliferation and function. These results indicate that HA scaffolds with the columnar microstructure could be used for bone repair applications in vivo.     

Hardystonite improves biocompatibility and strength of electrospun polycaprolactone nanofibers over hydroxyapatite: A comparative study

The aim of this study was to compare physico-chemical and biological properties of hydroxyapatite (HA) and hardystonite (HS) based composite scaffolds. Hardystonite (Ca₂ZnSi₂O₇) powders were synthesized by a sol–gel method while polycaprolactone–hardystonite (PCL–HS) and polycaprolactone–hydroxyapatite (PCL–HA) were fabricated in nanofibrous form by electrospinning. The physico-chemical and biological properties such as tensile strength, cell proliferation, cell infiltration and alkaline phosphatase activity were determined on both kinds of scaffolds. We found that PCL–HS scaffolds had better mechanical strength compared to PCL–HA scaffolds. Addition of HA and HS particles to PCL did not show any inhibitory effect on blood biocompatibility of scaffolds when assessed by hemolysis assay. The in vitro cellular behavior was evaluated by growing murine adipose-tissue-derived stem cells (mE-ASCs) over the scaffolds. Enhanced cell proliferation and improved cellular infiltrations on PCL–HS scaffolds were observed when compared to HA containing scaffolds. PCL–HS scaffolds exhibited a significant increase in alkaline phosphatase (ALP) activity and better mineralization of the matrix in comparison to PCL–HA scaffolds. These results clearly demonstrate the stimulatory role of Zn and Si present in HS based composite scaffolds, suggesting their potential application for bone tissue engineering.     

Proliferation and function of MC3T3-E1 cells on freeze-cast hydroxyapatite scaffolds with oriented pore architectures

Previous work by the authors showed that hydroxyapatite (HA) scaffolds with different types of oriented microstructures and a unique ‘elastic–plastic’ mechanical response could be prepared by unidirectional freezing of suspensions. The objective of the present work was to evaluate the in vitro cellular response to these freeze-cast HA scaffolds. Unidirectional scaffolds with approximately the same porosity (65–70%) but different pore architectures, described as ‘lamellar’ (pore width = 25 ± 5 μm) and ‘cellular’ (pore diameter = 100 ± 10 μm), were evaluated. Whereas both groups of scaffolds showed excellent ability to support the proliferation of MC3T3-E1 pre-osteoblastic cells on their surfaces, scaffolds with the cellular-type microstructure showed far better ability to support cell proliferation into the pores and cell function. These results indicate that freeze-cast HA scaffolds with the cellular-type microstructure have better potential for bone repair applications.     

三维打印羟基磷灰石晶须增强复合骨修复支架

利用三维打印技术成功制备羟基磷灰石晶须(HAPw)增强的聚己内酯(PCL)复合骨修复支架。通过改变三维打印的挤出速度和挤出气压, 使不同含量HAPw均能在PCL基材中一致排列并均匀分布。PCL支架的机械强度随HAPw含量增加显著提高, 添加33wt%HAPw使PCL支架强度提升了高达3倍。此外, HAPw使PCL支架表面与水的接触角从近100º降低至约50º, 有效改善了细胞表面粘附。经过体外人类骨髓间充质干细胞(hBMSC)在支架上的培养实验, 发现添加HAPw的复合支架具有更好的生物相容性, 能够有效促进hBMSC的增殖生长, 且HAPw-PCL复合支架上细胞具有更高的碱性磷酸酶(ALP)活性和OCN、RUNX2等相关成骨基因表达, 显示出hBMSCs向成骨方向更好的分化及成骨活性。