Photopatterned Dendrons for Tissue Engineering Applications

用于组织工程应用的光图案化树突

• 批准号: EP/G049572/1
• 负责人: Paul De Bank
• 金额: $ 38.59万
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG049572%2F1
• 关键词: Photopatterned; Dendrons; Tissue; Engineering; Applications

The fields of tissue engineering and regenerative medicine aim to replace or repair tissues and organs compromised by injury or disease. The ideal scenario for generating a laboratory-grown tissue is to harvest cells from a suitable source (ideally the patient), grow them in culture until there are a sufficient number and then transfer them to a three-dimensional (3D) polymer scaffold to give shape to the tissue. Here they are given the necessary chemical and physical cues to enable them to develop into a functional construct which is then implanted into the patient.However, there are a number of problems and technical hurdles that must be overcome for this to become a reality, especially for more complex tissues. One problem concerns the materials used to form the 3D cell scaffolds. For cells to adhere to and grow on a scaffold, the material must possess adhesive sites for the cells to recognize. Many polymers commonly used in tissue engineering have excellent biocompatibility and biodegradability, both desirable properties of a scaffold, but have limited cell-adhesive areas. A number of strategies exist to alter the surface properties of these materials in order to greatly increase cell adhesion, but all suffer from drawbacks such as the use of expensive, specialized equipment or degradation of the polymer. A more fundamental problem in tissue engineering and regenerative medicine strategies, however, is the spatial arrangement of cells. In natural tissues, the complex arrangement of multiple cell types in defined 3D architectures has a great influence on the function and survival of the tissue. Currently, we can not recreate this organization in the laboratory, instead largely relying on random seeding of cells, and this is particularly problematical if we want to incorporate blood vessels and nerves into lab-grown tissues.This research proposal will address both of these problems by developing a novel strategy to pattern polymeric materials with molecules that display multiple copies of cell-adhesive peptides. This will ultimately allow sequential seeding and growth of multiple cell types in defined arrangements, recreating the organization found in real tissues. To fully exploit the chemical functionality found in many polymers and the limited number of functional groups that can be chemically introduced into others without degradation occurring, the effective number of available adhesive sites will be dramatically increased by coupling dendrons to scaffold surfaces. These branched molecules contain multiple groups at the tips of their branches so, by attaching cell-adhesive peptides to each end group, each of the polymer's available functional groups will be made to display multiple adhesive species.Although modification of polymers with dendrons could be used as a stand-alone technique for increasing cell adhesion, the problem of cell patterning will also be addressed by decorating polymer surfaces with the dendrons in specific patterns. The basis of this technique is the initial modification of the scaffolds by covalent attachment of caged linker molecules, i.e. reactive chemical functionalities which are masked by a protecting group. These cages can be selectively removed by exposure to ultraviolet (UV) light and the resulting unmasked chemical group then used to attach cell-adhesive dendrons. Patterning using this technique will be achieved by UV exposure through patterned masks, resulting in a corresponding pattern of uncaged functional groups. Dendrons will be attached to the reactive, UV-exposed areas leaving the rest of the surface functionalities caged, and cells will be grown on the adhesive patterns. The process will then be repeated for subsequent patterning of other cell types. Ultimately, the utility of this technique will be demonstrated by patterning and co-culture of muscle and nerve cells to promote the site-specific formation of synaptic connections between the two cell types.

组织工程和再生医学领域旨在替换或修复因损伤或疾病而受损的组织和器官。产生实验室生长组织的理想方案是从合适的来源（理想情况下是患者）收获细胞，在培养物中培养它们直到有足够的数量，然后将它们转移到三维（3D）聚合物支架上以使组织成形。在这里，它们被赋予必要的化学和物理线索，使它们能够发育成功能性构建体，然后植入患者体内。然而，要实现这一目标，还必须克服许多问题和技术障碍，特别是对于更复杂的组织。一个问题涉及用于形成3D细胞支架的材料。为了使细胞粘附在支架上并在其上生长，材料必须具有粘附位点以供细胞识别。组织工程中常用的许多聚合物具有良好的生物相容性和生物降解性，这两种性能都是支架的理想性能，但具有有限的细胞粘附区域。存在许多策略来改变这些材料的表面性质，以大大增加细胞粘附，但所有这些策略都存在缺点，例如使用昂贵的专用设备或聚合物降解。然而，组织工程和再生医学策略中一个更基本的问题是细胞的空间排列。在天然组织中，多种细胞类型在限定的3D架构中的复杂排列对组织的功能和存活具有很大影响。目前，我们无法在实验室中重建这种组织，而主要依赖于随机接种细胞，如果我们想将血管和神经整合到实验室培养的组织中，这尤其成问题。这项研究计划将通过开发一种新的策略来解决这两个问题，即用显示多个细胞粘附肽拷贝的分子来图案化聚合物材料。这将最终允许多种细胞类型以限定的排列顺序接种和生长，重建在真实的组织中发现的组织。为了充分利用在许多聚合物中发现的化学官能度和可以化学引入到其他聚合物中而不发生降解的有限数量的官能团，将通过将树枝状分子偶联到支架表面来显著增加可用粘合位点的有效数量。这些分支分子在其分支的末端含有多个基团，因此，通过将细胞粘附肽连接到每个末端基团，将使聚合物的每个可用官能团显示多个粘附物质。虽然用树枝状分子修饰聚合物可以用作增加细胞粘附的独立技术，通过用特定图案的树枝状基元装饰聚合物表面，也可以解决细胞图案化的问题。该技术的基础是通过笼状连接分子的共价连接对支架进行初始修饰，即通过保护基掩蔽的反应性化学官能团。这些笼可以通过暴露于紫外线（UV）光选择性地去除，然后将所得的未掩蔽的化学基团用于附着细胞粘附性树突。使用该技术的图案化将通过图案化掩模的UV曝光来实现，从而产生未笼化官能团的相应图案。树枝状突起将附着在反应性、紫外线暴露区域，使其余表面功能被束缚，细胞将在粘合剂图案上生长。然后将重复该过程以用于其他细胞类型的后续图案化。最终，这项技术的实用性将通过肌肉和神经细胞的图案化和共培养来证明，以促进两种细胞类型之间突触连接的位点特异性形成。

项目成果

A hydrazide-anchored dendron scaffold for chemoselective ligation strategies.

• DOI: 10.1039/c4ob00870g
• 发表时间: 2014-08
• 期刊: Organic & biomolecular chemistry
• 影响因子: 3.2
• 作者: Liz O'Donovan;Paul A. De Bank