静电纺丝制备组织工程支架的研究进展

静电纺丝作为一种制备纳米纤维的技术,具有效率高、成本低、易实现等优点,已经成为制备组织工程支架的主要方法之一。简要介绍了组织工程及静电纺丝的原理;综述了几种单组分高分子组织工程支架的研究进展,并总结了静电纺丝制备多组分支架的方法;最后,提出了目前采用静电纺丝法制备组织工程支架存在的主要问题,并展望了未来的研究方向。     

溶胶-凝胶法制备生物微晶玻璃的研究进展

溶胶-凝胶法是一种材料合成新工艺,现已广泛用作生物植入体、组织工程支架及药物载体的生物活性玻璃粉体、块体玻璃、多孔生物微晶玻璃与涂层的制备.简要介绍了溶胺-凝胶法制备生物微晶玻璃的工艺原理和优缺点,着重分析了其研究和应用现状,并阐述了其发展前景.     

有机-无机复合骨重建材料的研究进展

骨组织重建技术的进步与材料科学的发展息息相关，对国内外当前非金属骨植入与骨组织工程材料的种类及其复合技术的研究情况进行了综述与评价，认为对界面结合的研究、新的智能型材料的研究是今后非金属复合骨重建材料的发展方向。     

Small extracellular vesicles secreted by urine-derived stem cells enhanced wound healing in aged mice by ameliorating cellular senescence

Regeneration of chronic skin wounds in tissue is still a key challenge in regenerative medicine because of the accumulation of senescent cells and increasing secretion of s¨enescence-associated secretory phenotype(SASP)in the wound site.Recently,some studies have reported that small extracellular vesicles(sEVs)derived from stem cells can alleviate cellular senescence with very low risk of tumorigenesis and immune responses.As our previous studies have shown that urine-derived stem cells(USCs)can be obtained easily and noninvasively and sEVs derived from USCs(USC-sEVs)have capabilities of regenerating tissue injuries,using USC-sEVs to enhance chronic skin wound healing in aged tissue might be a feasible and efficient strategy.Therefore,in this study,the USC-sEVs were collected and firstly loaded in a human acellular amniotic membrane(HAAM)for controlled releasing and locating the USC-sEVs in the wound site before they were implanted into a chronic skin wound in aged mice.In vivo results showed that the USC-sEVs in HAAM could effectively accelerate the wound healing by ameliorating cellular senescence and reducing the secretion of SASP in the aged skin wounds.To elucidate the mechanism,USC-sEVs were used to in vitro culture human dermal fibroblasts(HDFs)and results showed that USC-sEVs could rejuvenate senescent fibroblasts by reversing the aging phenotypes of senescent HDFs and efficiently reducing the secretion of SASP after they activated the Sirt1 pathway.Therefore,USC-sEVs are efficient for enhancing wound healing in aged mice by ameliorating cellular senescence.     

电纺纳米纤维构建组织工程支架研究新进展

电纺是制备纳米纤维的有效方法.纤维直径通常介于数十纳米至数微米之间,与细胞外基质中胶原等纤维支架的尺寸相近.采用天然高分子或合成高分子电纺纤维构建组织工程支架,可以仿生细胞外基质的结构乃至生物学功能,利于细胞的黏附、分化和增殖,引导组织的再生与修复,成为组织工程支架的研究热点.大量研究报道显示,电纺纳米纤维支架可以提供理想的细胞黏附、增殖和分化微环境.简要介绍了静电纺丝技术以及电纺纳米纤维的特点,重点总结了近几年来电纺纳米纤维在构建皮肤、血管、神经、骨与软骨等组织工程支架的研究进展,并展望了纳米纤维支架的应用前景.     

基于AR倒谱法研究人体脾组织微结构的变化

本文利用AR倒谱法对人体正常脾和脾增生组织的回波信号进行了分析,对软组织中散射元的平均间距进行了估计,结果表明：两种脾组织散射元的平均间距明显不同;AR倒谱能有效的反映软组织的微观结构特征,说明AR倒谱是软组织超声散射信号分析与软组织散射元平均间距定征的一种有效方法。     

Direct writing by way of melt electrospinning

Melt electrospun fibers of poly(?-caprolactone) are accurately deposited using an automated stage as the collector. Matching the translation speed of the collector to the speed of the melt electrospinning jet establishes control over the location of fiber deposition. In this sense, melt electrospinning writing can be seen to bridge the gap between solution electrospinning and direct writing additive manufacturing processes.     

快速溶剂萃取法分析组织样品中的二噁英(PCDDs)和多氯二苯呋喃(PCDFs)研究

本文分别采用快速萃取法和传统的索氏萃取法萃取组织样品中的二噁英(PCDDs)和多氯二苯呋喃(PC-DFs),采用高分辨率的气相色谱法/质谱法同位素稀释法进行分析。对两种萃取方法的数据进行比较。结果表明,快速溶剂萃取法具有和索氏萃取法相同的萃取能力,回收率相当,但是节省了大量的时间和试剂。因此,在实验室条件下,快速溶剂萃取法是一种可以替代索氏萃取法的新方法。     

多孔磷酸钙骨水泥组织工程支架的高分子灌注增强

利用棒状谷氨酸钠晶体作为造孔粒子,采用可溶盐造孔法,制备了三维连通的大孔径多孔磷酸钙骨水泥支架,分别将明胶(Gelatin) 、聚乳酸2羟基乙酸共聚物(PLGA) 、聚乳酸(PLA) 、聚己内酯(PCL) 、聚羟基丁酸戊酸酯(PHBV)灌注到多孔磷酸钙骨水泥(CPC)支架的孔隙中以改善支架材料的力学性能。结果表明,5 种高分子材料与水的接触角大小顺序为PHBV > PCL > PLA > PL GA > Gelatin , 复合支架材料的强度随高分子材料与水接触角的减小而增大;除PHBV外,其余4种均有明显的增强效果,其中Gelatin/CPC复合支架增强效果最好,强度达到2. 25 MPa±0. 02 MPa ,是CPC支架强度的25倍。经过增强的大孔径多孔磷酸钙骨水泥复合支架可用作骨组织工程支架材料。      

仿生法制备生物陶瓷涂层的最新研究进展

介绍了仿生制备生物陶瓷涂层的原理，工艺及在人体硬组织方面的应用，指出存在的问题和今后的发展趋势。     

静电纺制备的PLLA/PCL复合支架性能及细胞相容性

利用静电纺丝技术制备了一系列不同比例的左旋聚乳酸/聚己内酯(PLLA/PCL)复合纳米纤维支架。通过扫描电镜、差热分析、宽角X射线衍射和接触角测试手段对支架结构与形态、结晶性能及亲水性进行了表征;采用在缓冲溶液中加酶的方式,研究了复合材料的降解性能;将体外培养的真皮成纤细胞接种至材料表面,用扫描电镜观察了成纤细胞在材料表面的生长情况。研究结果表明,电纺丝得到的复合支架纤维直径均一,且呈相互连通的多孔网状结构;脂肪酶的存在加速了支架材料的降解速度;成纤细胞在复合支架上具有良好的生长状态。     

强激光对生物组织热作用的一个分析模型

本文在分析生物的传热传质过程的基础上 ,提出了结合实际的生物组织热作用的一个分析模型 :在诸相变边界上物性参数为阶跃函数的多边界 Stefan问题 .进行了一维问题的数值求解 ,它可以确定汽化区的尺寸以及边界的移动速度 ,进而估算出生物组织热损伤区的大小 .并将结果与实验进行了比较 ,来检验模型的合理性 ,得出该模型与实际生物组织热损伤过程相符合的结论     

Contractility-dependent modulation of cell proliferation and adhesion by microscale topographical cues

Engineering of cellular assembly on biomaterial scaffolds by utilizing microscale topographical cues has emerged as a powerful strategy in cardiovascular tissue engineering and regenerative medicine. However, the mechanisms through which these cues are processed to yield changes in canonical cell behaviors remain unclear. Previously, we showed that when mixtures of cardiomyocytes and fibroblasts were cultured on polydimethylsiloxane surfaces studded with microscale pillars (micropegs), fibroblast proliferation was dramatically suppressed, which suggests that the micropegs could be exploited to minimize fibrosis and scar formation. Here, we demonstrate that this effect relies on altered adhesive and micromechanical interactions between individual cells and micropegs. First, we show that the proliferation of a cell physically attached to a micropeg is significantly lower than that of a cell cultured on a featureless region of the substrate. Micropeg adhesion is accompanied by a marked elongation in cell and nuclear shape. When fibroblast contractility is pharmacologically attenuated through low-dose inhibition of either Rho-associated kinase or myosin light chain kinase, the potency with which micropeg adhesion suppresses cell proliferation is significantly reduced. Together, our results support a model in which cell fate decisions may be directly manipulated within tissue engineering scaffolds by the inclusion of microtopographical structures that alter cellular mechanics.     

高强度聚焦超声作用下的组织温度场测量技术的研究进展

高强度聚焦超声是近年来兴起的一种肿瘤无创治疗新技术,而温度监控是该治疗的关键,故温度场检测成为超声医学工程学研究的热点。该测量方法中的有损测温对实验操作要求较高,且易引起肿瘤细胞的转移;无损测温方法包括超声、微波辐射、电阻抗成像和MRI(磁共振)等,文章对这些新技术的优点和局限性作出综述。     

壳聚糖对骨组织工程中组织修复的影响

材料植入体内必然引起宿主体的应答,促进或抑制组织愈合。由于降解材料在体内的降解产物会随时间而变,产生的宿主体应答就会不同,进而会影响组织的愈合。而促进或抑制组织愈合的机制就成为新型医用高分子材料设计和制备的理论基础。壳聚糖是理想的骨组织修复材料之一,但至今还不清楚壳聚糖体内不同降解过程对组织修复的影响机制,也就无法设计出性能优良的壳聚糖基新材料。文章没有罗列壳聚糖基生物材料在骨组织工程中应用所取得的进展,而是重点阐述了壳聚糖在骨组织工程中应用的复杂性和对组织修复的影响,探讨了壳聚糖进一步用于骨组织工程所需要解决的问题。     

In vitro evaluation of borate-based bioactive glass scaffolds prepared by a polymer foam replication method

Borate-based bioactive glass scaffolds with a microstructure similar to that of human trabecular bone were prepared using a polymer foam replication method, and evaluated in vitro for potential bone repair applications. The scaffolds (porosity = 72 ± 3%; pore size = 250–500 μm) had a compressive strength of 6.4 ± 1.0 MPa. The bioactivity of the scaffolds was confirmed by the formation of a hydroxyapatite (HA) layer on the surface of the glass within 7 days in 0.02 M K₂HPO₄ solution at 37 °C. The biocompatibility of the scaffolds was assessed from the response of cells to extracts of the dissolution products of the scaffolds, using assays of MTT hydrolysis, cell viability, and alkaline phosphatase activity. For boron concentrations below a threshold value (0.65 mM), extracts of the glass dissolution products supported the proliferation of bone marrow stromal cells, as well as the proliferation and function of murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed attachment and continuous increase in the density of MLO-A5 cells cultured on the surface of the glass scaffolds. The results indicate that borate-based bioactive glass could be a potential scaffold material for bone tissue engineering provided that the boron released from the glass could be controlled below a threshold value.