纳米羟基磷灰石/胶原蛋白/丝素蛋白复合骨组织工程支架材料的生物相容性

背景:通过将两种及两种以上材料共混制备复合支架材料可以弥补各自的不足,利用各种材料的互补特性来满足组织工程对支架的要求。目的:制备纳米羟基磷灰石/胶原蛋白/丝素蛋白复合三维支架材料,并研究其细胞相容性。方法:将纳米羟基磷灰石、胶原蛋白与丝素蛋白分别按质量比为1∶1∶5、1∶2∶5、1∶3∶5的比例混合,制备纳米羟基磷灰石/胶原蛋白/丝素蛋白复合材料,测试其孔隙率、孔径大小、吸水膨胀率及压缩力学性能。将表征结果良好的质量比为1∶2∶5的纳米羟基磷灰石/胶原蛋白/丝素蛋白复合材料与MC3T3-E1细胞体外复合培养,MTT法检测复合培养2,4,6,8,12 d后的细胞活性。结果与结论:羟基磷灰石/胶原蛋白/丝素蛋白按质量1∶2∶5的比例混合更符合要求:孔径98-260μm,孔隙率为(96.72±2.78)%,吸水膨胀率为(549.37±35.29)%,生物力学试验机测定其力学性能稳定、压缩应变及弹性模量等指标适宜骨组织工程研究应用。MC3T3-E1细胞在纳米羟基磷灰石/胶原蛋白/丝素蛋白复合三维支架上生长增殖良好,表明纳米羟基磷灰石/胶原/丝素复合三维支架具有良好的细胞相容性。     

多孔型丝素蛋白/羟基磷灰石复合脂肪间充质干细胞修复兔股骨骨缺损

背景:从蚕丝中提取的丝素蛋白具有良好的细胞相容性,且可生物降解,用于修饰生物材料能提高细胞在材料表面的黏附和生长能力.目的:探讨丝素蛋白,羟基磷灰石材料复合脂肪间充质干细胞修复包含性骨缺损的作用.方法:取2月龄新西兰大白兔附睾处脂肪组织,经胰酶消化传代培养脂肪间充质干细胞,取第3代兔脂肪问充质干细胞以1 ×10~(10)L~(-1)浓度接种于丝素蛋白/羟基磷灰支架材料上,培养3h后加入含有1 μmol/L地塞米松、50 pmol/L维生素C、10 mmol/Lβ-甘油磷酸钠的DMEM培养液进行成骨诱导.新西兰大白兔36只,在兔股骨远端制备直径4.5 mm、深10mm的松质骨缺损.细胞复合材料组植入复合脂肪间充质干细胞的丝素蛋白,羟基磷灰石;单纯材料组植入丝素蛋白,羟基磷灰石;空白对照组不作任何植入.结果与结论:12周时大体观察细胞复合材料组骨缺损区完全被骨组织修复,单纯材料组骨缺损区缩小、部分修复,空白对照组骨缺损无修复.12周时X射线、组织学检查显示细胞复合材料组完全修复了骨缺损区,材料组部分修复了骨缺损区,细胞复合材料组的新生骨小梁多于单纯材料组(P<0.05),空白对照组未见骨修复.结果说明复合脂肪间充质干细胞的丝素蛋白,羟基磷灰石修复兔股骨包含性骨缺损能力优于单纯丝素蛋白,羟基磷灰石材料.     

多孔丝素蛋白/羟基磷灰石复合脂肪间充质干细胞修复兔关节软骨及软骨下骨缺损

背景:丝素蛋白/羟基磷灰石是细胞立体培养的良好支架,是临床常用的骨缺损修复材料,具有良好的生物相容性.脂肪干细胞具有向骨及软骨细胞分化的潜能,适合骨软骨缺损修复.目的:观察转化生长因子β1和胰岛素样生长因子1联合成软骨诱导脂肪干细胞与丝素蛋白/羟基磷灰石复合后修复兔关节软骨及软骨下骨缺损的效果.方法:取新西兰大白兔56只,2只用于传代培养脂肪间充质干细胞,以3×109 L-1浓度接种到丝素蛋白/羟基磷灰石.其余54只新西兰大白兔,在股骨髁间制备软骨缺损模型,随机分为细胞复合材料组、单纯材料组和空白对照组,细胞复合材料组植入复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石;单纯材料组植入丝素蛋白/羟基磷灰石;空白对照组不作任何植入.从大体、影像学、组织学观察比较缺损的修复情况.结果与结论:12周时大体观察、CT、磁共振和组织学检查细胞材料复合组软骨及软骨下骨缺损区完全被软骨组织修复,修复组织与周围软骨色泽相近,支架材料基本吸收,未见明显退变和白细胞浸润,所有标本均未见丝素蛋白残留.单纯材料组缺损区缩小、部分修复,且呈纤维软骨样修复.空白对照组缺损无明显修复.提示复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石修复兔关节软骨及软骨下骨缺损能力优于单纯丝素蛋白/羟基磷灰石材料.丝素蛋白/羟基磷灰石复合脂肪间充质干细胞可形成透明软骨修复动物膝关节全层软骨缺损,重建关节的解剖结构和功能,可作为新型骨软骨组织工程支架.     

多孔丝素蛋白/羟基磷灰石复合脂肪间充质干细胞修复兔关节软骨及软骨下骨缺损

背景：丝素蛋白/羟基磷灰石是细胞立体培养的良好支架,是临床常用的骨缺损修复材料,具有良好的生物相容性。脂肪干细胞具有向骨及软骨细胞分化的潜能,适合骨软骨缺损修复。目的：观察转化生长因子β1和胰岛素样生长因子1联合成软骨诱导脂肪干细胞与丝素蛋白/羟基磷灰石复合后修复兔关节软骨及软骨下骨缺损的效果。方法：取新西兰大白兔56只,2只用于传代培养脂肪间充质干细胞,以3×109L-1浓度接种到丝素蛋白/羟基磷灰石。其余54只新西兰大白兔,在股骨髁间制备软骨缺损模型,随机分为细胞复合材料组、单纯材料组和空白对照组,细胞复合材料组植入复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石;单纯材料组植入丝素蛋白/羟基磷灰石;空白对照组不作任何植入。从大体、影像学、组织学观察比较缺损的修复情况。结果与结论：12周时大体观察、CT、磁共振和组织学检查细胞材料复合组软骨及软骨下骨缺损区完全被软骨组织修复,修复组织与周围软骨色泽相近,支架材料基本吸收,未见明显退变和白细胞浸润,所有标本均未见丝素蛋白残留。单纯材料组缺损区缩小、部分修复,且呈纤维软骨样修复。空白对照组缺损无明显修复。提示复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石修复兔关节软骨及软骨下骨缺损能力优于单纯丝素蛋白/羟基磷灰石材料。丝素蛋白/羟基磷灰石复合脂肪间充质干细胞可形成透明软骨修复动物膝关节全层软骨缺损,重建关节的解剖结构和功能,可作为新型骨软骨组织工程支架。     

丝素蛋白/羟基磷灰石复合支架对骨髓间充质干细胞增殖分化的支持:优于胶原海绵材料吗?

背景:传统的羟基磷灰石强度低、孔隙度小、骨诱导性和传导性较差.因此,人们采用各种方法制备羟基磷灰石生物复合材料,以改进其性能.目的:观察丝素蛋白,羟基磷灰石复合材料对骨髓间充质干细胞生物特性的影响,并与常用的胶原海绵相比较.设计、时间及地点:重复测量观察及多样本观察实验,于2007-01/2008-06在苏州大学附属第一医院骨科实验室完成.材料:丝素蛋白/羟基磷灰石纳米材料由苏州大学材料学院李明忠教授研制提供,胶原海绵购买于上海其胜公司.方法:取SD大鼠股骨和胫骨分离提取骨髓间充质干细胞,进行培养,传代.取第3代骨髓间充质干细胞分别接种到丝素蛋白/羟基磷灰石复合材料及三维胶原海绵材料上进行共培养.未加材料,单独培养细胞,作为空白对照组.主要观察指标:应用倒置显微镜观察细胞生长情况;在培养第2,4,6,8天用MTT法测定细胞增殖情况及测定碱性磷酸酶活性.结果:①倒置显微镜显示骨髓间充质干细胞能在两种材料上良好地黏附、增殖和生长.②MTT法检测显示两种材料上的细胞增殖明显,碱性磷酸酶活性随培养时间延长而增加,均高于空白对照组.结论:丝素蛋白/羟基磷灰石复合材料显示出良好的生物相容性,并能促进细胞生长分化,其有望成为胶原组织工程支架材料很好的补充和替代.     

丝素蛋白对纳米羟基磷灰石晶体生长的调控作用

背景:前期研究表明丝素蛋白含量对丝素蛋白/纳米羟基磷灰石复合材料性能与结构有一定影响。目的:观察丝素蛋白含量对纳米羟基磷灰石晶体生长的调控作用。方法:采用物理化学方法制备出含0,10%,20%,30%,40%丝素蛋白的丝素蛋白/纳米羟基磷灰石复合物,通过热重分析仪、傅里叶红外光谱仪、透射电镜、X射线粉末衍射仪分析丝素蛋白含量对纳米羟基磷灰石晶体生长的调控作用。结果与结论:丝素蛋白的加入对纳米羟基磷灰石晶体的成核和生长具有明显调控作用:在纳米羟基磷灰石晶粒沿c轴高度择优生长,长径比增大,形貌由短棒状调控为针状。丝素蛋白含量对纳米羟基磷灰石晶体的成核和生长影响微弱,但对晶粒在丝素蛋白基质的有序排布有明显的调控作用:当丝素含量为10%和20%时,纳米羟基磷灰石晶粒呈放射状有序排布;丝素含量为30%和40%时,纳米羟基磷灰石晶粒无序团聚,说明30%含量是丝素蛋白与纳米羟基磷灰石的饱和吸附临界点。     

丝素蛋白对纳米羟基磷灰石晶体生长的调控作用

背景：前期研究表明丝素蛋白含量对丝素蛋白/纳米羟基磷灰石复合材料性能与结构有一定影响。目的：观察丝素蛋白含量对纳米羟基磷灰石晶体生长的调控作用。方法：采用物理化学方法制备出含0,10%,20%,30%,40%丝素蛋白的丝素蛋白/纳米羟基磷灰石复合物,通过热重分析仪、傅里叶红外光谱仪、透射电镜、X射线粉末衍射仪分析丝素蛋白含量对纳米羟基磷灰石晶体生长的调控作用。结果与结论：丝素蛋白的加入对纳米羟基磷灰石晶体的成核和生长具有明显调控作用：在纳米羟基磷灰石晶粒沿c轴高度择优生长,长径比增大,形貌由短棒状调控为针状。丝素蛋白含量对纳米羟基磷灰石晶体的成核和生长影响微弱,但对晶粒在丝素蛋白基质的有序排布有明显的调控作用：当丝素含量为10%和20%时,纳米羟基磷灰石晶粒呈放射状有序排布;丝素含量为30%和40%时,纳米羟基磷灰石晶粒无序团聚,说明30%含量是丝素蛋白与纳米羟基磷灰石的饱和吸附临界点。     

丝素蛋白/羟基磷灰石复合材料吸水率的测定及其在SD大鼠体内的降解

背景：羟基磷灰石降解缓慢、脆性大，而丝素蛋白机械强度差，将两者复合，可能克服单个材料的缺点。目的：测试不同规格丝素蛋白／羟基磷灰石（silk fibroin／hydroxyapatite，SF／HA）复合材料的吸水率和体内降解速率，为进一步的成骨实验提供依据。设计、时间及地点：随机对照的体内及体外实验，于2006-09／2007-06在苏州大学附属第一医院骨科研究所实验室完成。材料：4种规格SF／HA—1、SF／HA-2、SF／HA-3、SF／HA-4及普通羟基磷灰石，各材料的差别主要是丝素蛋白与羟基磷灰石组成比、致孔剂量及添加剂量不同。方法：测定4种SF／HA复合材料和羟基磷灰石在0．5，2，6，12及24h不同时间点的吸水率。将4种SF／HA复合材料植入SD大鼠背部皮下，进行体内降解观察，以羟基磷灰石为对照组。主要观察指标：各材料的吸水率；大体及组织学检查观察材料植入SD大鼠背部后不同时间点的降解情况。结果：各材料吸水率趋势为SF／HA-3和SF/HA-4〉SF/HA-2及SF／HA-1〉羟基磷灰石；同一材料吸水率随时间延长变化不明显。羟基磷灰石、SF／HA-1及SF／HA-2降解十分缓慢或基本不能降解：SF／HA-3于20-24周降解完毕；SF／HA-4于12～16周降解完毕；各种材料周围组织未见明显变性坏死等。结论：丝素蛋白能改善羟基磷灰石的理化性能，并可调控SF／HA的降解速率，SF／HA复合材料具有良好的组织相容性，有望成为一种新的骨修复替代材料。     

多孔型丝素蛋白/羟基磷灰石复合骨髓间充质干细胞修复兔半月板无血运区软骨损伤

背景:随着组织工程的兴起,半月板无血运区损伤的修复可能性显著地提高,但单一的支架材料均不能符合理想支架的要求,有一定的局限性。目的:观察丝素蛋白/羟基磷灰石复合骨髓间充质干细胞修复兔半月板无血运区软骨损伤的效果。方法:体外分离培养兔骨髓间充质干细胞,并定向诱导成纤维软骨细胞,与丝素蛋白/羟基磷灰石复合培养。42只构建半月板无血运区软骨损伤模型成功的大白兔随机抽签法均分为3组,复合材料组植入骨髓间充质干细胞-丝素蛋白/羟基磷灰石复合物;单纯材料组植入丝素蛋白/羟基磷灰石;对照组不行任何干预。结果与结论:复合材料组大体观察损伤被修复组织填充,8~12周效果逐渐改善,与正常半月板组织相似,优于其他两组;组织学检查显示8周时出现软骨囊和排列紊乱的胶原纤维,12周时完全修复了半月板损伤区,表现为纤维软骨样组织愈合;单纯材料组部分修复了半月板损伤区,呈瘢痕愈合,对照组未见软骨修复。MRI检查显示复合材料组修复效果较好;说明丝素蛋白/羟基磷灰石复合骨髓间充质干细胞可有效地修复半月板无血运区缺损。丝素蛋白/羟基磷灰石材料作为半月板软骨组织工程支架材料的良好生物相容性。     

丝素/壳聚糖/纳米羟基磷灰石构建的骨组织工程支架***

背景：丝素蛋白、壳聚糖及纳米羟基磷灰石均是天然材料,具有良好的生物活性和理化特性,作为人体组织工程材料已取得了一定的成果,但3种材料在单独应用的研究中还存在一定的缺陷。目的：制作丝素蛋白/壳聚糖/纳米羟基磷灰石三维支架材料,分析其特性。方法：将丝素蛋白、壳聚糖、纳米羟基磷灰石分别配制成2%的溶液后,分别按照1∶1∶0.5,1∶1∶1,1∶1∶1.5的体积比混合,采用冷冻干燥与化学交联技术制备成三维复合支架材料。检测三维复合支架的孔隙率、吸水膨胀率及热水溶失率,采用材料力学测验机测试干燥三维复合支架材料的拉伸和压缩弹性模量,采用扫描电镜检测三维复合支架的孔径。结果与结论：丝素蛋白/壳聚糖/纳米羟基磷灰石三维复合支架在干燥状态下呈白色,无特殊气味,为稳定固态的圆柱体,触之有明显的抗压能力和弹性。随着复合支架材料中纳米羟基磷灰石含量的增高,支架材料的孔隙率、吸水膨胀率、平均孔径呈逐渐减小趋势,热水溶失率及抗压能力表现出相反的趋势,结果显示以1∶1∶1体积比制作的支架更符合骨替代材料要求,其平均孔径为85.67μm、吸水膨胀率的为(135.65±4.56)%、热水溶失率为(22.84±1.06)%,支架材料内部孔隙均匀,呈现网状结构,孔隙之间交通发达,网状结构本身约10μm。     

Hydroxyapatite‐intertwined hybrid nanofibres for the mineralization of osteoblasts

Advances in tissue engineering have enabled the development of bioactive composite materials to generate biomimetic nanofibrous scaffolds for bone replacement therapies. Polymeric biocomposite nanofibrous scaffolds architecturally mimic the native extracellular matrix (ECM), delivering tremendous regenerative potential for bone tissue engineering. In the present study, biocompatible poly(l ‐lactic acid)‐co‐poly(ε‐caprolactone)–silk fibroin–hydroxyapatite–hyaluronic acid (PLACL–SF–HaP–HA) nanofibrous scaffolds were fabricated by electrospinning to mimic the native ECM. The developed nanofibrous scaffolds were characterized in terms of fibre morphology, functional group, hydrophilicity and mechanical strength, using SEM, FTIR, contact angle and tabletop tensile‐tester, respectively. The nanofibrous scaffolds showed a higher level of pore size and increased porosity of up to 95% for the exchange of nutrients and metabolic wastes. The fibre diameters obtained were in the range of around 255 ± 13.4–789 ± 22.41 nm. Osteoblasts cultured on PLACL–SF–HaP–HA showed a significantly (p < 0.001) higher level of proliferation (53%) and increased osteogenic differentiation and mineralization (63%) for the inclusion of bioactive molecules SF–HA. Energy‐dispersive X‐ray analysis (EDX) data proved that the presence of calcium and phosphorous in PLACL–SF–HaP–HA nanofibrous scaffolds was greater than in the other nanofibrous scaffolds with cultured osteoblasts. The obtained results for functionalized PLACL–SF–HaP–HA nanofibrous scaffolds proved them to be a potential biocomposite for bone tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.     

Transient bioelectrical devices inspired by a silkworm moth breaking out of its cocoon

Transient devices have attracted extensive interest because they allow changes in physical form and device function under the control of external stimuli or related commands and have very broad application prospects for information security, biomedical care and the environment. Transient bioelectrical devices were fabricated inspired by a silkworm moth breaking out of its cocoon, which has shown many advantages, including the use of mild stimulation, biocompatible materials, a simple process, and a universal strategy. For the fabrication of the transient devices, heat-sensitive microspheres with a 9.3 mol L⁻¹ LiBr solution in wax shells were prepared by microfluidic technology, which were then assembled into silk fibroin (SF) electronic materials/devices, such as SF conductive film, an LED circuit on SF film, and a Ag/SF film/Pt/SF film memristor. The contribution from the LiBr/wax microspheres to the transient time of the SF films upon exposure to heat was quantitatively investigated. This approach was applied to transiently dissolve a flexible Ag-nanowire resistance circuit line on a SF substrate. Moreover, memristors constructed with a functional layer of SF were destroyed by melting the LiBr/wax microspheres. This technique paves the way for realizing transient bioelectrical devices inspired by biological behavior, which have been well optimized by nature via evolution.

Silk fibroin-based transient devices were developed using LiBr/wax microspheres that mimic a silk cocoon protecting silkworm pupa and a juvenile moth secreting an enzyme to dissolve silk sericin and break a silk cocoon.     

Electrospun silk fibroin/TiO2 mats. Preparation,characterization and efficiency for the photocatalytic solar treatment of pesticide polluted water

The photocatalytic properties of silk fibroin (SF) incorporating TiO₂ nanoparticles using an electrospinning technique were examined. Electrospun SF/TiO₂ mats were successfully prepared and characterized by different techniques (XRD, FE-SEM, XPS, XDS, FTIR and BET). The photocatalytic efficiency of these materials were assessed by their ability to degrade four pesticides (boscalid, hexythiazox, pyraclostrobin and trifloxystrobin) in water exposed to solar irradiation. The effect of catalyst loading on the disappearance kinetics of the different pesticides was studied in order to determine the maximum degradation efficiency. The degradation rate significantly increases upon adding the TiO₂. However, no significant differences (p < 0.05) were observed when the TiO₂ loading was increased from 25 to 50 mg for most compounds. Thus, SF mats with 25 mg of TiO₂ were selected. Therefore, a new and simple approach to produce materials with photocatalytic activity, safety and potential application in the purification of water contaminated by pesticides has been developed.

The photocatalytic properties of silk fibroin (SF) incorporating TiO₂ nanoparticles using an electrospinning technique were examined.     

Facile synthesis of novel dopamine-modified glass fibers for improving alkali resistance of fibers and flexural strength of fiber-reinforced cement

Glass fiber-reinforced cementitious material is one of the significant components in structural materials playing vital roles in enhancing the tensile and flexural behavior of cement-based quasi-brittle materials. Compared with carbon and polymer fibers, its intrinsic similar silicate-based composition to cement was endowed with better bonding properties and compatibility with cement-based materials. However, the poor alkali resistance of glass fibers restrained their potential development for spreading to applications in construction fields. In this study, dopamine-modified glass fibers (DP) were self-polymerized at ambient temperature by a facile method for enhancing the alkali resistance of glass fibers. Scanning electron microscopy and X-ray photoelectron spectroscopy were utilized for characterizing DP. The duration of reaction and fiber to solution ratio were adjusted with an optimal reaction time of 12 h and fiber to solution ratio of 0.12 g ml⁻¹ acquired. Alkali resistance was measured by strength retention tests in both mortar and sodium hydroxide solution. Compared with untreated glass fibers (UN), DP exhibited a distinct improvement in strength retention rate of 37.1% and 18.9% under mortar and sodium hydroxide solution environments, respectively. Also, flexural strength tests of DP-reinforced cement were conducted, and its strength was increased in comparison with that of UN-reinforced cement by 58.2%. As a consequence, a novel simple method for improving the alkali resistance of glass fibers was proposed and is anticipated to promote the development and applications of glass-fiber reinforced cement-based materials.

In situ modification on fibers: in situ modification of self-polymerized dopamine on glass fibers was adjustably established. Relying on such nanomodification on the surface, a drastic enhancement of alkali resistance of glass fibers could be achieved.     

丝素蛋白/壳聚糖三维支架材料的制备方法

背景:很多研究表明丝素蛋白、壳聚糖为天然高分子材料,无毒无味,有良好的生物特性和理化性质。目的:探讨符合软骨组织工程支架材料要求的丝素蛋白/壳聚糖三维支架材料制备方法。方法:将丝素蛋白与壳聚糖按质量比分别为3∶1,1∶1,1∶3,0∶1的比例混合制备丝素蛋白-壳聚糖复合材料,通过孔径大小、孔隙率、吸水膨胀率及热水溶失率的测定,寻找丝素蛋白/壳聚糖最佳混合比例。结果与结论:丝素蛋白/壳聚糖按质量1∶1的比例混合更符合要求:孔径90～280μm,平均孔径为151.72μm;孔隙率为(92.72±4.78)%;吸水膨胀率为(141.10±6.87)%;热水溶失率交联后较交联前降低,交联前后比较差异有显著性意义(P<0.05)。说明丝素蛋白/壳聚糖按1∶1复合支架材料符合软骨组织工程支架材料理化性质的要求,该材料有望作为软骨组织工程研究较理想的支架材料。     

透明质酸改性的聚乳酸支架

背景:聚乳酸材料不具备细胞外基质材料的良好细胞亲和性能,采用化学方法将透明质酸交联制得的水凝胶具有良好的生物相容性。目的:以透明质酸对新型多孔隙率聚乳酸支架的进行改性,观察改性后支架的细胞相容性的改变。方法:采用盐析法制备出高孔隙率聚乳酸支架,采用低浓度NaOH进行表面轻度水解后,利用EDC和透明质酸进行支架的改性。结果与结论:透明质酸改性聚乳酸支架在扫描电镜下显示为多微孔的三维立体结构,孔壁及界面平滑,孔隙之间可见更细小微孔相连。改性聚乳酸支架水滴渗入较快,改性后多孔支架的保水能力与吸水能力得到明显的改善;透明质酸改性聚乳酸支架上细胞黏附及增殖优于未改性聚乳酸支架。透明质酸改性聚乳酸组软骨细胞生长密度及基质分泌更加旺盛。表明透明质酸改性聚乳酸多孔支架仍保持多孔的三维结构,其水亲和力、吸水能力、保水能力和细胞相容性均得到明显改善。