新型多孔偏磷酸钙复合膜的制备及细胞相容性*

背景：前期研究制备的多孔聚3-羟基丁酸-4-羟基丁酸/偏磷酸钙复合膜厚度较厚，且孔洞不均匀。
　　目的：制备厚度薄且分布均匀的多孔聚3-羟基丁酸-4-羟基丁酸/偏磷酸钙复合膜，检测其细胞相容性及对细胞分化的作用。
　　方法：通过相分离法制备厚度薄且分布均匀的无孔及多孔聚3-羟基丁酸-4-羟基丁酸/偏磷酸钙复合膜，检测其厚度及失重率。将人骨髓间充质干细胞分别与无孔及多孔聚3-羟基丁酸-4-羟基丁酸/偏磷酸钙复合膜共培养7 d，扫描电镜观察复合膜的超微结构，流式细胞术分析复合膜上骨髓间充质干细胞的表面标记物。
　　结果与结论：多孔和无孔复合膜的厚度分别为(0.041±0.005) mm和(0.058±0.004) mm，24 h失重率分别为19.93%和7.64%。无孔复合膜上的偏磷酸钙粒子分布均匀，细胞完全铺展，呈梭形；多孔复合膜上的偏磷酸钙粒子分布均匀，孔径分布也均匀，孔径2-8μm，细胞全完铺展，呈多边形，有多个触角，部分细胞触角进入支架内部。无孔与多孔复合膜上的细胞均表达CD105、CD90、CD44、CD29及CD73，组间细胞阳性率差异无显著性意义。实验制备的聚3-羟基丁酸-4-羟基丁酸/偏磷酸钙复合膜具有良好的细胞相容性，但无促细胞分化作用。     

聚羟基丁酸已酯-聚乳酸材料改性应用于组织工程隆鼻充填材料的可行性

目的:观察以改性聚羟基丁酸已酯即聚羟基丁酸已酯与聚乳酸共混的组织工程软骨做为隆鼻充填材料的可行性。方法:实验于2005-07/11在解放军第四军医大学附属西京医院整形外科实验室完成。①取兔耳软骨细胞的分离、培养并鉴定。②预先将聚羟基丁酸已酯-聚乳酸制备成1.5cm×1.0cm的瓦状形态膜片,表面以聚羟基丁酸已酯-聚乳酸制成的纺丝反复缠绕,形成“三明治”样结构,进行预处理。③进行细胞-支架复合物的体外构建及培养,收集体外扩增的第3代软骨细胞,接种于聚羟基丁酸已酯-聚乳酸支架上。④取3周龄新西兰兔12只,采用随机数字法将其分成实验组和对照组,每组各6只。实验组:将细胞-支架复合物置于兔的鼻背部骨膜下,观察软骨形成情况;对照组:单纯以未接种软骨细胞的支架移植于兔背部皮下。于相同时间点进行检测。结果:经过大体、组织染色及扫描电镜检查发现:①实验组:植入4周后该复合物在兔鼻背下支架表层有软骨层形成,并可见软骨细胞突入至支架材料内部;8周后支架材料继续降解,软骨细胞及细胞基质生成明显,伴有胶原长入。②对照组:植入4周、8周支架材料外周先形成一层透明组织薄膜,周围无炎性细胞浸润,内部为聚羟基丁酸已酯-聚乳酸支架材料,随着时间延续,周围纤维组织增生,支架材料出现不同程度的降解,不能维持原有的空间结构,较实验组结构崩解明显。未见有类软骨样组织形成。结论:以改性聚羟基丁酸已酯(聚羟基丁酸已酯-聚乳酸共混物)做为支架材料构建的组织工程软骨,可用于隆鼻的充填材料。     

聚β-羟基丁酸脂支架材料用于大鼠前脂肪细胞移植

背景:利用组织工程技术将前脂肪细胞在体外与生物支架粘附培养后进行细胞移植中首先要解决支架材料与细胞的生物相容性问题。目的:探讨聚β-羟基丁酸脂支架材料用于前脂肪细胞移植的可行性。设计:随机对照实验。材料:实验于2003-10/2005-06在武汉大学医学院完成,选用12只雄性SD大鼠,体质量200～250g,由武汉大学医学院实验动物中心提供。聚β-羟基丁酸酯支架材料由清华大学化工系高分子材料研究所提供。方法:将大鼠的前脂肪细胞分离,体外纯化培养备用,将聚β-羟基丁酸酯支架材料制成0.75cm×0.75cm×0.2cm大小的片状,经含有150g/L胎牛血清DMEM/F12培养液浸泡并置于培养板内,每孔1片,共12孔,每孔内加入培养好的细胞悬液1.0mL形成细胞生物支架复合体。取8只大鼠,将制成的复合体手术植入大鼠右侧背部皮下组织并用5-0丝线固定为细胞支架组,以相同方式将未粘附细胞的生物支架植于同一大鼠左侧背部皮下组织内为空白支架组。每侧各植入1片,8周后取材,观察移植物外观及结构变化并测量其重量和体积。4只大鼠植入其余4片细胞生物支架,植入3周取出,经100g/L中性甲醛固定后,苏木精-伊红染色,切片,观察其组织学变化。主要观察指标:①细胞支架组与空白支架组移植物大体与组织学观察结果。②两组移植物体积及质量比较。结果:纳入大鼠12只均进入结果分析。①细胞支架组与空白支架组移植物大体观察结果:细胞支架组植入片外观呈肉红色,周边有包膜形成,可见新生细小血管长入材料内。空白支架组外观为灰白色,外被包膜。②两组移植物苏木精-伊红染色观察结果:3周后细胞支架组移植物周边有少许散在脂肪细胞,血管数较少,8周后复合体周边为薄层纤维包膜,可见脂肪细胞由支架周边向内长入并伸入支架内,有的部分几乎被脂肪细胞充满,并见有较多血管形成;空白支架组仅见包膜及血管,支架内充满纤维结缔组织,未见脂肪细胞生长。③两组移植物体积及质量比较结果:细胞支架组支架体积大于空白支架组[(257.5±70.2),(144.6±62.6)mm3,P<0.01],质量大于空白支架组[(245.6±58.2),(148.7±60.3)mg,P<0.01]。结论:前脂肪细胞可在聚β-羟基丁酸酯支架上粘附,增殖并分化为成熟的脂肪细胞,聚β-羟基丁酸酯材料作为前脂肪细胞的移植载体是可行的。     

羟基丁酸-羟基辛酸聚合物-胶原骨软骨支架的制备及应用

背景：关节软骨修复的关键是软骨和软骨下骨的整体修复,然而目前尚缺乏理想的一体化支架。目的：制备聚羟基丁酸-羟基辛酸-胶原一体化支架,并分析其基本生物学特性。方法：以聚羟基丁酸-羟基辛酸、Ⅰ型胶原为材料,通过溶剂浇铸-颗粒沥滤法制备聚羟基丁酸-羟基辛酸-胶原一体化支架,观察支架超微结构,支架孔径及孔与孔的连通情况;液体置换法测定支架孔隙率。将乳兔骨髓间充质干细胞接种于聚羟基丁酸-羟基辛酸-胶原一体化支架上,扫描电镜观察细胞在支架上的黏附状态,MTT法测定细胞在支架上的生长曲线。结果与结论：一体化支架呈疏松多孔结构,软骨层孔径80-100μm,骨层孔径200-220μm,孔隙率（80.0±2.3）%。骨髓间充质干细胞在支架上黏附状态良好,增殖迅速。说明聚羟基丁酸-羟基辛酸-胶原骨软骨一体化支架具备适宜的孔隙结构和良好的生物亲和性。     

聚羟基丁酸与羟基辛酸骨组织工程支架的表面修饰

目的:研究多聚赖氨酸表面修饰的聚羟基丁酸与羟基辛酸骨组织工程支架对细胞黏附、增殖及分化的影响.方法:冷冻干燥/颗粒沥滤法制备聚羟基丁酸与羟基辛酸多孔支架,将其置于0.1,1.0,10 g/L的多聚赖氨酸溶液中,负压排气吸附进行表面修饰.灭菌后的支架置于48孔板,接种兔骨髓间充质干细胞.分别于1,4,7,10,14 d取样.结果:3个多聚赖氨酸修饰组的细胞黏附率均高于支架-细胞组(P<0.01),且细胞黏附率随多聚赖氨酸修饰质量浓度的增大而显著提高.1,4 d时10 g/L多聚赖氨酸修饰组的细胞增殖活性和碱性磷酸酶活性均高于其他两组,但至10,14 d时却低于其他两组.结论:多聚赖氨酸修饰的聚羟基丁酸与羟基辛酸多孔支架有利于提高骨髓间充质干细胞的黏附率,但1.0 g/L的多聚赖氨酸修饰更有利于细胞的增殖与促成骨分化.     

聚羟基丁酸-羟基异戊酯与绵羊软骨细胞的相容性

背景:聚羟基丁酸-羟基异戊酯是微生物在生长条件不平衡状态时合成的产物,具有可降解性、热塑性,作为组织工程的新犁支架材料,越来越受到重视.目的:评估聚羟基丁酸-羟基异戊酯作为组织工程支架,与绵羊关节软骨细胞的相容性.设计、时间及地点:体外埘比观察实验,于2005-11/2007-05在中山大学附属第三医院中心实验室和广东冠吴生物科技公司动物手术室完成.材料:聚羟基丁酸-羟基异戊酯膜和泡沫样三维支架由华南理工大学材料学院提供.6月龄雄性实验绵羊1只,体质量17kg,由广东冠吴生物科技公司提供.方法:切取绵羊膝关节软骨后,分离、原代培养软骨细胞,将第2代软骨细胞接种至聚羟基丁酸-羟基异戊酯膜和泡沫样三维支架上,以单纯细胞培养为对照.主要观察指标:扫描电镜观察细胞形态,计数1,2,6 h时的细胞黏附率:按培养液量与支架体积10 mL/cm3为标准浓度制备浸提液,并制备标准浓度1/16～16倍的浸提液,以MTT法检测细胞毒性;流式细胞仪分析接种到材料上的细胞周期,计算增殖指数;接种于聚羟基丁酸-羟基异戊酯二维支架上4,8,12 d,以Hoechst33258荧光法定量测定细胞内DNA含量,二甲基亚甲蓝法测定糖胺聚糖含量.结果:第2代软骨细胞在聚羟基丁酸-羟基异戊酯膜上6 h的黏附率75.6%,与对照组比较差异无显著性;9个浓度梯度的浸提液毒性均为O级;扫描电镜观察见细胞在聚羟基丁酸-羟基异戊酯膜上伸展良好,形态佳,细胞间连接正常,在三维支架的孔隙内立体生长,并分泌大量基质;流式细胞分析接种于材料上的细胞周期无变化;与培养瓶内软骨细胞相比,8d时,聚羟基丁酸-羟基异戊酯三维支架上的细胞内牯胺聚糖浓度显著增高,12 d时,支架上的细胞内DNA量显著增高.结论:聚羟基丁酸-羟基异戊酯作为软骨组织工程支架材料,与绵羊关节软骨细胞具有良好的生物相容性,但早期细胞黏附率低,是其小足.     

羟基丁酸-羟基辛酸一体化骨软骨支架的体外血管化

背景：前期实验构建的羟基丁酸-羟基辛酸共聚体一体化骨软骨支架具备良好的生物相容性、生物可降解性，并且降解产物无毒性。 目的：将兔肾微血管内皮细胞与羟基丁酸-羟基辛酸一体化骨软骨支架复合培养，观察支架骨层血管化效果。方法：运用溶剂浇铸-颗粒沥滤法，制备具有骨层/骨与软骨界面层/软骨层3层结构的羟基丁酸-羟基辛酸一体化骨软骨支架。将传代培养至第3代的兔肾微血管内皮细胞，接种到一体化骨软骨支架骨层支架上，MTT法检测细胞在支架上的增殖活性，10 d后苏木精-伊红染色及电镜观察细胞在支架内的生长状况。 结果与结论：一体化骨软骨支架外观具备明显的3层结构，各层之间连接紧密，骨层疏松多孔，各层支架孔隙均匀且相通，一体化支架孔隙率为78%。兔肾微血管内皮细胞在支架上分裂增殖良好，复合培养10 d后，细胞在骨层支架内呈立体生长，中间界面层内未发现细胞，苏木精-伊红染色可见细胞黏附生长于骨层支架孔隙间，细胞依附支架的多孔结构生长，形成管腔样结构，但细胞并未长入中间界面层。     

聚羟基丁酸已酯-聚乳酸材料改性应用于组织工程隆鼻充填材料的可行性

目的：观察以改性聚羟基丁酸已酯即聚羟基丁酸已酯与聚乳酸共混的组织工程软骨做为隆鼻充填材料的可行性。 方法：实验于2005—07／11在解放军第四军医大学附属西京医院整形外科实验室完成。①取兔耳软骨细胞的分离．培养并鉴定。②预先将聚羟基丁酸已酯-聚乳酸制备成1．5cm&;#215;1．0cm的瓦状形态膜片，表面以聚羟基丁酸已酯-聚乳酸制成的纺丝反复缠绕，形成“三明治”样结构，进行预处理。③进行细胞-支架复合物的体外构建及培养，收集体外扩增的第3代软骨细胞，接种于聚羟基丁酸已酯-聚乳酸支架上。④取3周龄新西兰兔12只，采用随机数字法将其分成实验组和对照组，每组各6只。实验组：将细胞-支架复合物置于兔的鼻背部骨膜下，观察软骨形成情况；对照组：单纯以未接种软骨细胞的支架移植于兔背部皮下。于相同时间点进行检测。 结果：经过大体．组织染色及扫描电镜检查发现：①实验组：植入4周后该复合物在免鼻背下支架表层有软骨层形成，并可见软骨细胞突入至支架材料内部；8周后支架材料继续降解，软骨细胞及细胞基质生成明显，伴有胶原长入。②对照组：植入4周、8周支架材料外周先形成一层透明组织薄膜，周围无炎性细胞浸润，内部为聚羟基丁酸已酯-聚乳酸支架材料，随着时间延续，周围纤维组织增生，支架材料出现不同程度的降解，不能维持原有的空间结构，较实验组结构崩解明显。未见有类软骨样组织形成。 结论：以改性聚羟基丁酸已酯（聚羟基丁酸已酯-聚乳酸共混物）做为支架材料构建的组织工程软骨，可用于隆鼻的充填材料。     

电纺丝聚乳酸、聚3羟基丁酸酯共聚4羟基丁酸酯和聚碳酸亚丙酯纳米纤维的制备及表面亲水性(英文)

背景:近年来聚乳酸、羟基磷灰石类复合材料支架具有良好的生物降解性和生物相容性而被广泛的研究,但是这类复合材料在增强材料界面的结合、调节材料的降解速率、改善材料的强度等方面仍不能满足理想的组织工程支架材料的要求.目的:探讨电纺丝法制备纳米纤维的结构形态及表面亲水性.方法:分别将聚乳酸、聚3羟基丁酸酯共聚4羟基丁酸酯和聚碳酸亚丙酯通过静电纺丝法制备纳米纤维膜,扫描电镜对纤维膜的结构形态进行分析,并观察在人体环境相近的磷酸盐缓冲溶液(37℃,pH 7.4)中浸泡不同时间的表面亲水性.结果与结论:通过静电纺丝技术可以将聚乳酸、聚3羟基丁酸酯共聚4羟基丁酸酯和聚碳酸亚丙酯3种材料制各成微纳米纤维结构,控制制备参数可以获得不同直径的纤维,样品随着在培养液中的浸泡时间延长,总体显示出接触角比初始降低,亲水性增强.     

聚羟基丁酸酯-聚羟基己酸酯共聚物/氧化异丙烯F-127复合支架构建人组织工程软骨

目的:探讨聚羟基丁酸酯-聚羟基己酸酯共聚物/氧化异丙烯F-127复合支架作为软骨组织工程支架的可行性。方法:实验于2004-09/2005-04在中国医科大学整形外科医院外耳整形与再造中心完成。①选取4周龄无胸腺雄性裸鼠8只,左侧背部皮下为软骨细胞-支架复合物组,右侧背部皮下为单纯支架对照组。人软骨细胞来源于中国医科大学整形外科医院外耳整形与再造中心临床小耳畸形患者行肋软骨移植时剩余的边脚料分离软骨细胞。聚羟基丁酸酯-聚羟基己酸酯共聚物泡沫材料由清华大学化工系提供,1.0cm×1.0cm×0.3cm大小,环氧乙烷消毒后备用。②消化、分离、培养人肋软骨细胞,将第3代细胞制成悬液,细胞浓度为5×1010L-1。取1mL软骨细胞悬液与少量30%氧化异丙烯F-127溶液(4℃)均匀混合后接种至聚羟基丁酸酯-聚羟基己酸酯共聚物支架上,形成细胞-生物材料复合物,体外培养1周后植入软骨细胞-支架复合物组,单纯支架对照组植入单纯聚羟基丁酸酯-聚羟基己酸酯共聚物/氧化异丙烯F-127复合支架。③术后12周取材,行大体观察。利用苏木精-伊红染色、甲苯胺蓝染色、阿尔辛蓝-丽春红染色对再生的软骨组织进行组织学检测。结果:实验选取4周龄无胸腺雄性裸鼠8只,全部进入结果分析。①术后12周大体标本观察结果:软骨细胞-支架复合物组形成了与支架形态相同的乳白色类似软骨样组织,表面光滑有弹性。单纯支架对照组呈褐色,质地较软。②再生的软骨组织术后12周组织学检查结果:组织学检查证实软骨细胞-支架复合物组有软骨细胞存在,并且有基质分泌。单纯支架对照组无新生软骨组织形成。结论:利用聚羟基丁酸酯-聚羟基己酸酯共聚物/氧化异丙烯F-127复合支架可在裸鼠体内形成人组织工程化软骨。     

Electrospun porous poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/lecithin scaffold for bone tissue engineering

Bone tissue engineering has emerged as a promising restorative strategy for bone reconstruction and bone defect repair. It is challenging to establish an appropriate scaffold with an excellent porous microstructure for bone defects and thereby promote bone repair. In this study, electrospinning as a simple and efficient technology was employed to fabricate a porous poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) scaffold coated with lecithin. The morphology, phase composition, and physical properties of the electrospun P34HB/lec scaffold were characterized. Meanwhile, cellular behaviors of bone marrow mesenchymal stem cells (BMSCs), including proliferation, adhesion, migration, osteogenic differentiation, and related gene expression, were also investigated. Finally, a rat subcutaneous implant model and a calvarial defect model were used to evaluated the biocompatibility and effect of these scaffolds on bone repair, respectively. The in vitro results demonstrated that these electrospun fibers were interwoven with each other to form the porous P34HB/lec scaffold and the addition of lecithin improved the hydrophilicity of the pure P34HB scaffold, enhanced the efficiency of cell migration, and decreased inflammatory response. Furthermore, the in vivo results showed that P34HB/lec scaffold had excellent biocompatibility, improved the vascularization, and promoted the bone regeneration. All these results indicated that nanofibers of P34HB scaffolds in combination with the lecithin could exert a synergistic effect on promoting osteogenesis and regeneration of bone defects; thus, the P34HB scaffold with lecithin showed great application potential for bone tissue engineering.

An electrospun P34HB scaffold was prepared and coated with lecithin. As a scaffold for bone tissue engineering, the P34HB/lec scaffold could promote proliferation and osteogenesis of BMSCs in vitro, and also accelerate bone regeneration in vivo.     

不同光固化方法对可压型及通用型树脂硬度的影响

背景:弱光启动是近年来应用于临床的新的固化方法,其对复合树脂的性能具有一定的影响,以往国外的研究主要是针对通用型树脂进行的,而对可压型树脂的研究报道较少.目的:课题提出弱光启动固化对可压型复合树脂硬度产生影响的假设,并希望与通用型复合树脂进行比较加以验证.设计、时间及地点:双因素设计实验,于2007-10在中山大学附属第一医院口腔科和广东出入境检验检疫局检验检疫技术中心化矿金属材料实验室进行.材料:3种可压型复合树脂为:EcuShere-Carat(简称EC,德国DMG公司),Filtek P60(简称P60,美国3M EPSE公司),Tetric Ceram HB(简称HB,列支敦士登Ivoclar Vivadent公司):通用型复合树脂为Filtek Z250(简称Z250,美国3M EPSE公司).所有树脂颜色均为A3.方法:将3种可压型树脂及1种通用型树脂充填入直径7 mm、高4 mm的圆柱形容器中,每种树脂20个样本,分别以两种方法固化(每种10个样本).弱光启动固化照射方法为300 mW/cm2照射10 S,600 mW/cm2照射30 S,常规光固化照射方法为600 mW/cm2照射40 s.主要观察指标:用维氏显微硬度计测量样本表面及底面的维氏显微硬度.结果:可压型复合树脂的硬度高于通用型复合树脂;弱光启动固化虽使3种可压型树脂表面硬度及底面硬度降低,但与常规光固化比较差别无显著性意义(P＞0.05);弱光启动固化使通用型树脂表面及底面硬度均降低,两种固化方法差别有显著性意义(P＜0.05).结论:课题结论提示临床应根据不同的充填部位选择树脂种类以及光固化的具体方法.     

Poly‐ε‐caprolactone scaffold and reduced in vitro cell culture: beneficial effect on compaction and improved valvular tissue formation

Tissue‐engineered heart valves (TEHVs), based on polyglycolic acid (PGA) scaffolds coated with poly‐4‐hydroxybutyrate (P4HB), have shown promising in vivo results in terms of tissue formation. However, a major drawback of these TEHVs is compaction and retraction of the leaflets, causing regurgitation. To overcome this problem, the aim of this study was to investigate: (a) the use of the slowly degrading poly‐ε‐caprolactone (PCL) scaffold for prolonged mechanical integrity; and (b) the use of lower passage cells for enhanced tissue formation. Passage 3, 5 and 7 (P3, P5 and P7) human and ovine vascular‐derived cells were seeded onto both PGA–P4HB and PCL scaffold strips. After 4 weeks of culture, compaction, tissue formation, mechanical properties and cell phenotypes were compared. TEHVs were cultured to observe retraction of the leaflets in the native‐like geometry. After culture, tissues based on PGA–P4HB scaffold showed 50–60% compaction, while PCL‐based tissues showed compaction of 0–10%. Tissue formation, stiffness and strength were increased with decreasing passage number; however, this did not influence compaction. Ovine PCL‐based tissues did render less strong tissues compared to PGA–P4HB‐based tissues. No differences in cell phenotype between the scaffold materials, species or cell passage numbers were observed. This study shows that PCL scaffolds may serve as alternative scaffold materials for human TEHVs with minimal compaction and without compromising tissue composition and properties, while further optimization of ovine TEHVs is needed. Reducing cell expansion time will result in faster generation of TEHVs, providing more rapid treatment for patients. Copyright © 2013 John Wiley & Sons, Ltd.     

添加剂对偏磷酸钙玻璃陶瓷多孔性能的影响

目的：偏磷酸钙（calcium metaphosphate，CMP）玻璃陶瓷的多孔性能与许多因素相关，如钙磷比、添加剂含最和烧制温度等。通过改变添加剂含量制备不同孔隙率的CMP玻璃陶瓷，观察其成孔差异和降解性能。方法：实验于2006-01/2007-06在暨南大学生物医学工程系和测试中心完成。采用二次烧结法制备3种不同配方的CMP玻璃陶瓷，其配方的主要差异在于添加剂（由Al2O3、MgO、CaF2按3：2：1摩尔比例组成）的含量不同，分别为5.4％，6．0％，6．7％。用分析天平称质量，计算3种样品的吸水率、显气孔率和体积密度。采用X射线衍射仪进行3种样品的晶相分析，扫描电镜观察3种样品的表面形貌。计算3种样品的失质量百分比评价其降解性能。结果：①随着添加剂含量的增加，吸水率和显气孔率增大，体积密度减少。②3种样品的X射线衍射图谱基本无差异，结合PCPDFWIN数据库，可知3种CMP玻璃陶瓷的主晶相均为β-Ca（PO3）2晶体。扫描电镜结果表明，随着添加剂含量的增加，样品孔洞数目减少，孔洞直释越来越大。③随着添加剂含量的增加，3种样品的失重百分比分别为7．7％，5．9％和3．4％。结论：通过改变添加剂的含量，可改变钙磷比相同的CMP玻璃陶瓷的多孔性能和降解性能。     

A novel porous egg-white (EW)/titania composite photocatalytic material for efficient photodegradation applications

A novel porous egg-white (EW)/titania composite material was prepared via a facile nonaqueous precipitation method with EW as the porous skeleton. In a typical process, tetrabutyl titanate, a titanium precursor, was dissolved in ethanol to undergo a non-hydrolytic reaction with the aid of anhydrous formic acid under ultrasonication and form a porous structure with EW. The composite material was characterized by BET, XRD, FTIR spectroscopy, TEM, FE-SEM and photocatalytic degradation test. The results show that formic acid changes the characteristic structure of tetrabutyl titanate, increases the polarity of its C–O and Ti–O bonds, and promotes the non-hydrolytic de-etherization poly-condensation reaction. After ultrasonic treatment, the reaction product was rearranged to form anatase titania on EW to form a porous structure. The porous composite material had a mean pore size of 15.8 nm, BET surface area of 325.5 m² g⁻¹ and exhibited an excellent photocatalytic activity. The degradation rate of methyl orange using the EW/titania composite material reached 99.9% in 50 minutes, exhibiting an attractive prospect in wastewater treatment.

A novel porous egg-white (EW)/titania composite material was prepared via a facile nonaqueous precipitation method with EW as the porous skeleton.     

Enhanced thermoelectric performance of CNT/P3HT composites with low CNT content

Carbon nanotubes (CNTs) have emerged as one of the leading additives for improving the thermoelectric properties of organic materials due to their unique structure and excellent electronic transport properties. However, since as-grown CNTs generally possess different diameters, it is of high interest to determine the influence of the diameter of carbon nanotubes on the thermoelectric properties of CNT/poly(3-hexylthiophene) (P3HT) composite films. Herein, we prepared CNT/P3HT composite films with diameters of <8 nm, 8–15 nm, 20–30 nm, 30–50 nm and >50 nm and studied their thermoelectric properties. It was found that the diameter of CNTs had an important influence on the TE performance of the composite films. The P3HT-d_CNT (<8 nm) and P3HT-d_CNT (8–15 nm) composite films exhibited almost the same thermoelectric performance and almost more than double that of the other three composite films with increased CNT diameter. The different mass fractions of CNT/P3HT composite films have also been investigated. The maximum TE power factor of CNT (d < 8 nm)/P3HT composite films reached 49.0 μW mK⁻² at the mass fraction of 95 wt% P3HT, that is, 5 wt% CNTs. This superior TE power factor of CNT (d < 8 nm)/P3HT composite films can be ascribed to the fully connected interlayer of the P3HT polymer and also the heterogeneous dispersion of short-length CNTs.

The maximum TE power factor of CNT (d < 8 nm)/P3HT composite films reached 49.0 μW mK⁻² at the mass fraction of 5 wt% CNTs.     

Sodium alginate/collagen composite multiscale porous scaffolds containing poly(ε-caprolactone) microspheres fabricated based on additive manufacturing technology

Biocompatible porous scaffolds with adjustable pore structures, appropriate mechanical properties and drug loading properties are important components of bone tissue engineering. In this work, biocompatible sodium alginate (SA)/collagen (Col) multiscale porous scaffolds containing poly(ε-caprolactone) microspheres (Ms-PCL) have been facilely fabricated based on 3D extrusion printing of the pre-crosslinked composite hydrogels. The prepared composite hydrogels can be 3D extrusion printed into porous scaffolds with different designed shapes and adjustable pore structures. The hydroxyapatite (HAP) nanoparticles have been added into the SA/Col hydrogels to achieve stress dispersion and form double crosslinking networks. SA-Ca²⁺ crosslinking networks and Col–genipin (GP) crosslinking networks have been constructed to improve the mechanical properties of the scaffolds (about 2557 kPa of compressive stress at 70% strain), and reduce the swelling rate and degradation rate of SA/Col scaffolds. Moreover, the SA/Col hydrogels contain hydrophobic antibacterial drug enrofloxacin loaded Ms-PCL, and in vitro drug release research shows a sustained-release function of porous scaffolds, indicating the potential application of SA/Col porous scaffolds as drug carriers. In addition, the antibacterial experiments show that the composite scaffolds display a distinguished and long-term antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, mouse bone mesenchymal stem cells (mBMSCs) are seeded on the SA/Col composite scaffolds, and an in vitro biocompatibility experiment shows that the mBMSCs can adhere well on the composite scaffolds, which indicate that the fabricated composite scaffolds are biocompatible. In short, all of the above results suggest that the biocompatible SA/Col composite porous scaffolds have enormous application and potential in bone tissue engineering.

Biocompatible porous scaffolds with adjustable pore structures, appropriate mechanical properties and drug loading properties are important components of bone tissue engineering.     

Unidirectional neuronal cell growth and differentiation on aligned polyhydroxyalkanoate blend microfibres with varying diameters

Polyhydroxyalkanoates (PHAs) are a family of prokaryotic‐derived biodegradable and biocompatible natural polymers known to exhibit neuroregenerative properties. In this work, poly(3‐hydroxybutyrate), P(3HB), and poly(3‐hydroxyoctanoate), P(3HO), have been combined to form blend fibres for directional guidance of neuronal cell growth and differentiation. A 25:75 P(3HO)/P(3HB) blend (PHA blend) was used for the manufacturing of electrospun fibres as resorbable scaffolds to be used as internal guidance lumen structures in nerve conduits. The biocompatibility of these fibres was studied using neuronal and Schwann cells. Highly aligned and uniform fibres with varying diameters were fabricated by controlling electrospinning parameters. The resulting fibre diameters were 2.4 ± 0.3, 3.7 ± 0.3, and 13.5 ± 2.3 μm for small, medium, and large diameter fibres, respectively. The cell response to these electrospun fibres was investigated with respect to growth and differentiation. Cell migration observed on the electrospun fibres showed topographical guidance in accordance with the direction of the fibres. The correlation between fibre diameter and neuronal growth under two conditions, individually and in coculture with Schwann cells, was evaluated. Results obtained from both assays revealed that all PHA blend fibre groups were able to support growth and guide aligned distribution of neuronal cells, and there was a direct correlation between the fibre diameter and neuronal growth and differentiation. This work has led to the development of a family of unique biodegradable and highly biocompatible 3D substrates capable of guiding and facilitating the growth, proliferation, and differentiation of neuronal cells as internal structures within nerve conduits.     

多孔聚乳酸／骨基质明胶生物活性复合材料骨诱导活性实验

背景: 目前复合材料已成为骨移植材料研究的热点, 多孔聚乳酸 /骨基质明胶复合活性材料的应用有待研究。目的: 采用超临界二氧化碳合成法制备多孔聚乳酸 / 骨基质明胶复合活性材料, 体外评价其骨形成能力。设计: 观察对比实验。单位: 南方医科大学组织工程研究中心, 中国辐射防护研究院生物材料制药技术研究所。材料: 小鼠 MC3T3-E1 成骨前体细胞从日本 RIKEN 细胞库获得, 聚乳酸由暨南大学提供。碱性磷酸酶检测试剂为南京建成生物工程研究所产品。小鼠 MC3T3-E1 成骨前体细胞在含 100 g/L 胎牛血清 ( 四季青) 、100 mg/L 青霉素和 100 U/L 链霉素的 DMEM 培养基(Gibco, 美国) 培养, 用 0.25%胰酶(Gibco, 美国) 传代。方法: 实验于 2005- 10/2006- 07 在南方医科大学组织工程研究中心广东省重点实验室完成。采用超临界二氧化碳法制备多孔聚乳酸 / 骨基质明胶复合材料, 并通过大体及扫描电镜观察复合情况。在体外将聚乳酸、聚乳酸 / 骨基质明胶与 MC3T3-E1 小鼠成骨前体细胞共培养, 分别为聚乳酸组及聚乳酸 / 骨基质明胶组, 正常培养基作为对照组, 数码相机拍摄每组培养孔图像, 图像处理与分析软件测定被染色面积占培养孔面积百分比, 即为钙化结节面积百分比。采用细胞超声裂解法检测各组细胞内钙含量及碱性磷酸酶活性。主要观察指标: ①聚乳酸 / 骨基质明胶大体及扫描电镜观察结果; ②钙化面积的定量测定。③钙含量及碱性磷酸酶活性测定。结果: ①聚乳酸 / 骨基质明胶大体及扫描电镜观察结果: 复合材料骨基质明胶与聚乳酸混合均匀, 材料孔隙分布均匀, 孔隙大小在 50～150 μm之间, 孔洞联通性好。在这些大孔隙的壁上, 仍有大量 5～10 μm 的孔隙。②钙化结节面积测定结果: 聚乳酸 / 骨基质明胶复合材料组、聚乳酸组、空白对照组钙化结节形成面积百分比分别为 (42.98±4.44)%,(9.55±1.94)%, (0.86±0.41)%, 组间比较差异均有统计学意义 (P <0.01) 。③钙含量及碱性磷酸酶测定结果: 聚乳酸 / 骨基质明胶复合材料组、聚乳酸组和空白对照组的碱性磷酸酶活性分别为 (5 427.58±1 173.57), (1 060.54±500.27), (40.01±24.50) nkat/g, 组间比较均有统计学意义(P < 0.05～0.01) ; 聚乳酸 / 骨基质明胶复合材料组钙含量为(3.51±1.64)mmol/g, 高于聚乳酸组和空白对照组[(1.04±0.21) , (0.70±0.24)mmol/g, P < 0.01]。结论: 采用超临界二氧化碳合成法制备的聚乳酸 /骨基质明胶多孔复合支架材料具有良好的骨诱导活性, 有可能作为一种有前景的骨植入材料及骨组织工程支架材料。