脱细胞基质水凝胶在再生医学中的研究进展

脱细胞基质(dECM)由于其高仿生性和优异的生物相容性,已被广泛用作再生医学的支架材料。水凝胶(hydrogel)作为一种高含水量、可控流动性的功能高分子材料,非常适合用于临床中的部分微创手术。近年来,随着水凝胶理论和技术的快速发展,dECM水凝胶逐渐成为再生医学领域的研究热点。本文从dECM水凝胶的制备及其临床前应用两个方面对近年来的相关研究进行综述,并展望其未来的临床前景。     

脱细胞基质制备方法及其在涎腺组织工程中的应用

背景:由脱细胞基质组成的生物支架被广泛应用于动物及临床研究,以修复和重建组织与器官,但所有的脱细胞方法都会在一定程度上破坏基质结构与功能。目的:综述脱细胞基质制备方法、优缺点及其在涎腺组织工程研究中的应用。方法:应用计算机检索CNKI数据库、中国生物医学文献数据库、PubMed数据库及Elsevier数据库2008至2019年发表的相关文献,检索词为“脱细胞基质,制备方法,涎腺,组织工程,再生;decellularization,preparation method,parotid gland tissue engineering”,共纳入74篇文献。结果与结论:大部分组织与器官脱细胞基质制备方法需要化学、生物(酶)、物理及以上几种方法联合使用,具体方法取决于组织与器官的厚度、组成和性质。虽然不是所有脱细胞方法均可去除组织与器官中的细胞成分,但完全去除细胞的组织与器官具有重塑组织特异性的优势,为接种细胞的增殖和分化提供有利的微环境。由于涎腺结构复杂和组织工程化在临床应用中的挑战,应用于患者的临床移植进展有限,该领域的体内研究仅限于动物,而基于颌下腺脱细胞基质生物支架材料方面的应用有望为涎腺组织工程提供有利的来源。     

水凝胶材料和间充质干细胞在组织工程中的应用进展

随着组织工程学的发展, 人们越来越关注将水凝胶作为支架材料并与细胞3D培养相结合用于组织器官再生与修复。水凝胶由亲水性聚合物、共聚物或可以形成大分子链的单体大分子交联而成, 可吸收大量水分并保持3D结构, 具有良好的生物相容性、可包埋细胞和有效的递送生物活性分子等特点, 因而被广泛用于生物医药领域的药物输送和组织工程等领域。间充质干细胞可以从骨髓、脂肪、脐带等多种组织中获取, 具有低免疫原性及多向分化潜能, 是细胞3D培养以及细胞治疗的首选。目前间充质干细胞主要是2D培养模式, 该培养模式下的间充质干细胞繁殖率低, 且无法模拟体内的生长环境。水凝胶材料作为3D细胞培养支架具有良好的相容性, 可以模拟体内的生长环境, 在修复受损软骨、骨、皮肤和心脏等组织中有巨大潜力。概述水凝胶、间充质干细胞以及间充质干细胞和水凝胶材料在组织工程中的应用, 展示水凝胶材料与间充质干细胞的3D培养在不同组织再生和修复中的发展趋势和可能性, 以期为后续水凝胶和干细胞的深入应用研究提供参考。     

制备脱细胞基质生物墨水在心血管疾病领域中的应用

背景：借助计算机辅助,3D生物打印技术利用负载活细胞的生物墨水实现组织器官的构建,这种技术设计自由度高、可个性化定制且制造灵活,为心血管组织工程构建带来了新希望。生物墨水是3D生物打印技术的关键,是生物材料与组织再生领域近年来的研究热点。脱细胞基质材料具有低免疫原性、维持原有细胞外基质组分与纤维结构以及利于组织特异性细胞的存活与扩增的特点,是一种具有潜力的生物墨水。目的：总结了脱细胞基质生物墨水的制备与性能表征方法及其在心血管领域中的应用,为脱细胞基质生物墨水在心血管领域中的应用研究提供重要参考。方法：在中国知网和PubMed数据库中进行相关文献检索,中文检索词为“3D打印、脱细胞、生物墨水、血管、心脏”,英文检索词为“decellularization,bioink,3D print,vessel,cardiac”,最终纳入82篇文献进行分析。结果与结论：(1)脱细胞基质生物墨水的基本制备步骤包括生物材料脱细胞处理获得脱细胞基质,酶解消化脱细胞基质,调节消化液pH值和渗透压以及脱细胞基质混合细胞;(2)脱细胞基质生物墨水的基本性能表征主要包括脱细胞基质组分、流变性能、微观结构、生物活...     

灌注法制备全肾脏脱细胞基质支架的体内生物相容性

背景：应用灌注法制备的大鼠全肾脏脱细胞基质支架具有良好的体外细胞相容性,但其体内生物相容性尚不明确。 目的：应用灌注法制备大鼠全肾脏脱细胞基质支架,检测其体内生物相容性。 方法：应用灌注法制备Wistar大鼠全肾脏脱细胞基质支架,进行以下实验：①急性毒性实验：在小鼠腹腔分别注射全肾脏脱细胞基质支架浸提液、生理盐水及苯酚。②溶血实验：将抗凝新西兰兔血分别与全肾脏脱细胞基质支架浸提液、生理盐水及蒸馏水混合。③热源实验：向新西兰兔耳缘静脉注射全肾脏脱细胞基质支架浸提液。④内皮刺激实验：在新西兰兔皮下注射全肾脏脱细胞基质支架浸提液,观察有无皮肤刺激反应。⑤皮下植入实验：将全肾脏脱细胞基质支架埋入新西兰兔背部皮下。 结果与结论：全灌注法制备的Wistar大鼠全肾脏脱细胞基质支架无细胞残留,未引起全身毒性反应、急性溶血反应、热源反应及皮肤刺激反应,植入兔体内具有良好的组织相容性。说明大鼠全肾脏脱细胞基质材料在动物体内具有很好的生物相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

兔肋软骨脱细胞基质的制备

背景：研究表明新西兰兔软骨组织可作为组织工程支架材料,其中关节软骨及耳软骨的脱细胞基质的研究较多,但采用肋软骨作为组织工程软骨支架的研究较少。 目的：制备新西兰兔肋软骨脱细胞基质,探讨天然软骨支架作为组织工程支架的可行性。 方法：用联合去垢剂-酶法获得软骨支架,根据脱细胞过程中Triton X-100第2次处理时间0,24,48,96 h分为4组。脱细胞完毕后各组支架固定行扫描电镜采集图像观察计算支架孔隙率、孔径长度,并对支架进行苏木精-伊红染色、甲苯胺蓝及Ⅱ型胶原免疫组织化学染色,并将脱细胞支架植入异体新西兰兔皮下观察其相容性。 结果与结论：兔肋软骨脱细胞基质呈乳白色,大小均一,染色示支架结构完整,仍保存大量酸性黏多糖及Ⅱ型胶原成分,扫描电镜观察经一定时间的脱细胞处理后可得到结构完整,孔隙均匀的天然软骨支架,其孔隙率为(61.31±8.45) %;孔径长度为(32.80±5.15) μm,符合正态性分布,各组脱细胞支架植入异体新西兰兔皮下7 d后生物相容性良好,周围软组织无明显充血、化脓等炎症排斥反应出现。结果显示,兔肋软骨脱细胞支架具有良好的基质组成,有较完整、均匀的孔隙结构及孔径分布,可作为组织工程支架材料。     

脱细胞基质软骨支架的制备

背景：脱细胞基质材料去除了天然材料中的细胞成分,保留了基质成分,有效降低了天然材料的免疫原性,同时能够保持材料的机械强度。 目的：拟利用洗脱方法去除兔肋软骨中的细胞基质,制备天然生物支架材料。 方法：取新西兰大白兔肋软骨,清除周围组织后随机分组处理,以未经处理的肋软骨作为正常对照组;48 h处理组以去污剂-酶化学消化48 h;96 h处理组以去污剂-酶化学消化96 h,3组均通过苏木精-伊红染色及电镜观察脱细胞效果。同时收集诱导第7天的兔骨髓间充质干细胞3×109 L-1,与同种异体肋软骨脱细胞基质体外复合培养,于第3,7天取复合物行电镜观察细胞在脱细胞基质表面的黏附生长情况。 结果与结论：新鲜肋软骨标本每个软骨陷窝内均有排列紧密的二三个软骨细胞,去污剂-酶化学消化后软骨陷窝内的细胞逐渐脱失,至消化处理96 h后,软骨陷窝内的细胞完全脱失。共培养第3天时,脱细胞基质表面有大量骨髓间充质干细胞分布,细胞为多角形,有伪足伸出,锚定在基质表面,部分区域可见细胞在基质表面增殖分裂;第7天时,脱细胞基质表面大部分均为细胞覆盖,细胞呈扁平状,有多个足突充分伸展,细胞之间互相连接,分泌大量细胞外基质沉积在基质表面,呈冰霜样改变,表明制备的脱细胞基质具有良好的细胞相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

脱细胞血管基质制备及体内外生物相容性

背景:利用脱细胞血管基质作为血管支架具有以下优点:脱细胞血管基质保留了自然血管的复杂三维结构;脱细胞基质表面的生长因子和结构域有利于细胞的黏附和浸润。目的:制备脱细胞血管基质并对其体内外生物相容性进行评价。方法:采用胰蛋白酶、Triton X-100逐步处理猪颈动脉制备脱细胞血管基质。采用皮下植入实验、急性毒性实验和体外细胞毒性实验等评价其生物相容性。结果与结论:脱细胞基质材料具有良好的化学稳定性,未释放对红细胞产生破坏溶解作用的有害元素,未引起急性溶血反应,对细胞的生长无毒性影响。脱细胞基质材料在动物体内植入后早期有较多炎性细胞浸润,到实验观察的后期无明显炎性细胞浸润,脱细胞基质内可见成纤维细胞。另外,脱细胞基质材料对周边组织未产生毒性作用,伤口Ⅰ期愈合。同时组织学切片显示:支架材料与周边组织相容性好,未产生排斥反应。说明脱细胞基质材料在动物体内具有很好的生物相容性。     

脱细胞基质复合支架在组织再生中的应用

背景：目前的脱细胞方法不可避免地会对脱细胞基质支架造成损伤,为更好地发挥其作为组织工程支架的优势,对脱细胞基质支架进行修饰以改善性能显得尤为重要。目的：综述脱细胞基质复合支架在组织再生中的应用进展。方法：以“decellularized extracellular matrix,tissue engineering,crosslinking,Electrospun nanofibers,3D bioprinting technology,tissue regeneration;脱细胞基质,组织工程,交联,静电纺丝纳米纤维,三维生物打印技术,组织再生”等作为关键词,在PubMed数据库、万方数据库、中国知网数据库进行检索,文献的语种限定为中文和英文,检索时限为2009-2022年。共检索到文献142余篇,最终纳入79篇进行综述。结果与结论：采用化学、物理及生物方法对组织或器官去除细胞的过程,会对脱细胞基质支架的超微结构造成损伤,导致支架的机械性能差与不可控的降解等。通过交联、静电纺丝技术、三维生物打印技术、纳米颗粒、甲氧基聚乙二醇及生长因子修饰构建复合支架,可优化脱细胞基质支架的性能,其...     

利用水凝胶设计组织再生微环境

水凝胶如何为细胞、组织的生长提供三维微环境已成为组织工程和再生医学领域的研究热点,生物活性分子修饰获得的智能水凝胶是能够促进组织再生的重要生物材料。根据水凝胶的来源,可将其分为天然和合成水凝胶两种类型。水凝胶的设计策略主要包括凝胶降解敏感位点的设计、生物黏附性的获得、生长因子和细胞因子对凝胶的修饰以及再生组织的血管重建。此外,本文以智能水凝胶在软骨组织工程、神经组织工程等方面的应用为例,阐述了水凝胶在组织工程和再生医学领域的突出研究进展。     

Fabrication and characterization of silk microfiber-reinforced methacrylated gelatin hydrogel with tunable properties

Abstract

Despite considerable research effort, the natural hydrogels presently available for tissue engineering suffer from several major drawbacks, one of the significant issue is their poor mechanical strength which are unable to satisfy some mechanical requirements for successful outcomes. Herein, to mimic the composition and structure of the natural extracellular matrix, the micron-sized silk fibers obtained by alkaline hydrolysis were used as a reinforcement phase in a GelMA hydrogel, resulting in a material with significantly greater stiffness than pure GelMA hydrogel alone. In addition, the hydrogel demonstrated tunable compressive strength, swelling capacity, and degradation properties based on the silk fiber length. Experiments with cells indicated that MC3T3-E1 pre-osteoblasts quickly adhered to and proliferated on the surface of the composite hydrogels, as revealed by FDA/PI staining and CCK-8 assays. In addition, various cellular responses, including cell adhesion, changes in cellular morphology and cell proliferation behavior, occurred on the composite hydrogel and varied with fiber length. Overall, this study introduces a series of fiber-reinforced, tunable composite hydrogels that could be useful for various tissue engineering applications.     

智能水凝胶在骨类硬组织再生和修复中的应用

BACKGROUND: Intelligent hydrogel as a new material is widely used in biological medicine, tissue engineering, memory element switch, biological enzyme immobilization and other related fields, and exhibits good biological characteristics. Intelligent hydrogels provide a new approach for regeneration and repair of bone and other hard tissues.  OBJECTIVE: To summarize the latest developments of intelligent hydrogel in the biological medicine and tissue engineering in order to find out new methods for regeneration and repair of bone and other hard tissues. METHODS: A computer-based research of CNKI, PubMed and EBSCO-MEDLINE databases was performed to retrieve relevant literatures about the application of intelligent hydrogel in regeneration and repair of bone and other hard tissues published from 2000 to 2015. The keywords were “hydrogel, bone tissue engineering, bone defect, regeneration, repair” in Chinese and English, respectively. RESULTS AND CONCLUSION: Intelligent hydrogels are classified into pH-sensitive, temperature-sensitive, light-sensitive, multiple-sensitive and other sensitive hydrogels. In order to improve the mineralization ability of the hydrogel and construct the three-dimensional polymer scaffold of hydrogel, the main structure of the hydrogel materials can be mixed with various signal factors, thus achieving the multi-utility and multi-function of the material system, which will become the development trend of tissue engineering construction.      

Smooth muscle cell growth in photopolymerized hydrogels with cell adhesive and proteolytically degradable domains: synthetic ECM analogs for tissue engineering

Photopolymerizable polyethylene glycol (PEG) derivatives have been investigated as hydrogel tissue engineering scaffolds. These materials have been modified with bioactive peptides in order to create materials that mimic some of the properties of the natural extracellular matrix (ECM). The PEG derivatives with proteolytically degradable peptides in their backbone have been used to form hydrogels that are degraded by enzymes involved in cell migration, such as collagenase and elastase. Cell adhesive peptides, such as the peptide RGD, have been grafted into photopolymerized hydrogels to achieve biospecific cell adhesion. Cells seeded homogeneously in the hydrogels during photopolymerization remain viable, proliferate, and produce ECM proteins. Cells can also migrate through hydrogels that contain both proteolytically degradable and cell adhesive peptides. The biological activities of these materials can be tailored to meet the requirements of a given tissue engineering application by creating a mixture of various bioactive PEG derivatives prior to photopolymerization.     

Hydrogels derived from demineralized and decellularized bone extracellular matrix

The extracellular matrix (ECM) of mammalian tissues has been isolated, decellularized and utilized as a scaffold to facilitate the repair and reconstruction of numerous tissues. Recent studies have suggested that superior function and complex tissue formation occurred when ECM scaffolds were derived from site-specific homologous tissues compared with heterologous tissues. The objectives of the present study were to apply a stringent decellularization process to demineralized bone matrix (DBM), prepared from bovine bone, and to characterize the structure and composition of the resulting ECM materials and DBM itself. Additionally, we sought to produce a soluble form of DBM and ECM which could be induced to form a hydrogel. Current clinical delivery of DBM particles for treatment of bone defects requires incorporation of the particles within a carrier liquid. Differences in osteogenic activity, inflammation and nephrotoxicity have been reported with various carrier liquids. The use of hydrogel forms of DBM or ECM may reduce the need for carrier liquids. DBM and ECM hydrogels exhibited sigmoidal gelation kinetics consistent with a nucleation and growth mechanism, with ECM hydrogels characterized by lower storage moduli than the DBM hydrogels. Enhanced proliferation of mouse primary calvarial cells was achieved on ECM hydrogels, compared with collagen type I and DBM hydrogels. These results show that DBM and ECM hydrogels have distinct structural, mechanical and biological properties and have the potential for clinical delivery without the need for carrier liquids.     

智能水凝胶在组织工程中的应用

背景：与传统水凝胶相比,智能水凝胶能够对外界刺激诸如温度、pH值、光、磁场等作出不同的应答表现,产生二级结构甚至化学结构的变化,自发组装形成有序的超分子结构,最终形成具有三维结构的凝胶。 目的：综述智能水凝胶的研究现状及其在组织工程的应用。 方法：应用计算机检索中国知网及PubMed 数据库从建库至2014年有关智能水凝胶在组织工程中应用的文献,检索关键词为“水凝胶,组织工程学,hydrogel,Tissue engineering”。 结果与结论：智能水凝胶中包括温度敏感性、pH敏感性、光敏感性、磁敏感性及温度/pH双重敏感性水凝胶,其对于外界环境变化能自动感知并能作出响应性的反应,在药物递送系统、药物释放,修复和改善缺损组织等领域表现出一系列传统材料所没有的突出性能,尤其是在组织工程方面表现出相当的优越性：低免疫原性,减少了炎症和排斥作用;具备生物可降解性;能真正在三维尺度上模拟细胞所处微环境,从而利于细胞黏附、生长、迁移及分化等。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

Surface functionalization of hyaluronic acid hydrogels by polyelectrolyte multilayer films

Hyaluronic acid (HA), an anionic polysaccharide, is one of the major components of the natural extracellular matrix (ECM). Although HA has been widely used for tissue engineering applications, it does not support cell attachment and spreading and needs chemical modification to support cellular adhesion. Here, we present a simple approach to functionalize photocrosslinked HA hydrogels by deposition of poly(l-lysine) (PLL) and HA multilayer films made by the layer-by-layer (LbL) technique. PLL/HA multilayer film formation was assessed by using fluorescence microscopy, contact angle measurements, cationic dye loading and confocal microscopy. The effect of polyelectrolyte multilayer film (PEM) formation on the physicochemical and mechanical properties of hydrogels revealed polyelectrolyte diffusion inside the hydrogel pores, increased hydrophobicity of the surface, reduced equilibrium swelling, and reduced compressive moduli of the modified hydrogels. Furthermore, NIH-3T3 fibroblasts seeded on the surface showed improved cell attachment and spreading on the multilayer functionalized hydrogels. Thus, modification of HA hydrogel surfaces with multilayer films affected their physicochemical properties and improved cell adhesion and spreading on these surfaces. This new hydrogel/PEM composite system may offer possibilities for various biomedical and tissue engineering applications, including growth factor delivery and co-culture systems.     

A hydrogel derived from decellularized dermal extracellular matrix

The ECM of mammalian tissues has been used as a scaffold to facilitate the repair and reconstruction of numerous tissues. Such scaffolds are prepared in many forms including sheets, powders, and hydrogels. ECM hydrogels provide advantages such as injectability, the ability to fill an irregularly shaped space, and the inherent bioactivity of native matrix. However, material properties of ECM hydrogels and the effect of these properties upon cell behavior are neither well understood nor controlled. The objective of this study was to prepare and determine the structure, mechanics, and the cell response in?vitro and in?vivo of ECM hydrogels prepared from decellularized porcine dermis and urinary bladder tissues. Dermal ECM hydrogels were characterized by a more dense fiber architecture and greater mechanical integrity than urinary bladder ECM hydrogels, and showed a dose dependent increase in mechanical properties with ECM concentration. In?vitro, dermal ECM hydrogels supported greater C2C12 myoblast fusion, and less fibroblast infiltration and less fibroblast mediated hydrogel contraction than urinary bladder ECM hydrogels. Both hydrogels were rapidly infiltrated by host cells, primarily macrophages, when implanted in a rat abdominal wall defect. Both ECM hydrogels degraded by 35 days in?vivo, but UBM hydrogels degraded more quickly, and with greater amounts of myogenesis than dermal ECM. These results show that ECM hydrogel properties can be varied and partially controlled by the scaffold tissue source, and that these properties can markedly affect cell behavior.     

Tetronic®-based composite hydrogel scaffolds seeded with rat bladder smooth muscle cells for urinary bladder tissue engineering applications

Natural hydrogels such as collagen offer desirable properties for tissue engineering, including cell adhesion sites, but their low mechanical strength is not suitable for bladder tissue regeneration. In contrast, synthetic hydrogels such as poly (ethylene glycol) allow tuning of mechanical properties, but do not elicit protein adsorption or cell adhesion. For this reason, we explored the use of composite hydrogel blends composed of Tetronic (BASF) 1107-acrylate (T1107A) in combination with extracellular matrix moieties collagen and hyaluronic acid seeded with bladder smooth muscle cells (BSMC). This composite hydrogel supported BSMC growth and distribution throughout the construct. When compared to the control (acellular) hydrogels, mechanical properties (peak stress, peak strain, and elastic modulus) of the cellular hydrogels were significantly greater. When compared to the 7-day time point after BSMC seeding, results of mechanical testing at the 14-day time point indicated a significant increase in both ultimate tensile stress (4.1–11.6 kPa) and elastic modulus (11.8–42.7 kPa) in cellular hydrogels. The time-dependent improvement in stiffness and strength of the cellular constructs can be attributed to the continuous collagen deposition and reconstruction by BSMC seeded in the matrix. The composite hydrogel provided a biocompatible scaffold for BSMC to thrive and strengthen the matrix; further, this trend could lead to strengthening the construct to match the mechanical properties of the bladder.     

Poly (ethylene glycol) hydrogel scaffolds with multiscale porosity for culture of human adipose-derived stem cells

Three-dimensional (3?D) hydrogel scaffolds are an attractive option for tissue regeneration applications because they allow for cell migration, fluid exchange, and can be synthesized to closely mimic the physical properties of the extracellular matrix environment. The material properties of hydrogels play a vital role in cellular migration and differentiation. In light of this, in-depth understanding of material properties is required before such scaffolds can be used to study their influence on cells. Herein, various blends and thicknesses of poly (ethylene glycol) dimethacrylate (PEGDMA) hydrogels were synthesized, flash frozen, and dried by lyophilization to create scaffolds with multiscale porosity. Environmental scanning electron microscopy (ESEM) images demonstrated that lyophilization induced microporous voids in the PEGDMA hydrogels while swelling studies show the hydrogels retain their innate swelling properties. Change in pore size was observed between drying methods, polymer blend, and thickness when imaged in the hydrated state. Human adipose-derived stem cells (hASCs) were seeded on lyophilized and non-lyophilized hydrogels to determine if the scaffolds would support cell attachment and proliferation of a clinically relevant cell type. Cell attachment and morphology of the hASCs were evaluated using fluorescence imaging. Qualitative observations in cell attachment and morphology of hASCs on the surface of the different hydrogel spatial configurations indicate these multiscale porosity hydrogels create a suitable scaffold for hASC culture. These findings offer another factor of tunability in creating biomimetic hydrogels for various tissue engineering applications including tissue repair, regeneration, wound healing, and controlled release of growth factors.