DNA-crosslinked gels: New advanced biomaterials

DNA 交联凝胶：新型先进生物材料

• 批准号: 7031036
• 负责人: NOSHIR A. LANGRANA
• 金额: $ 18.07万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-15 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7031036
• 关键词: DNA; SDS polyacrylamide gel electrophoresis; bioengineering /biomedical engineering; biomaterial development /preparation; biophysics; cell adhesion; cell differentiation; cell migration; cell morphology; copolymer; crosslink; elasticity; embryonic stem cell; extracellular matrix proteins; gel; miniature biomedical equipment; phase contrast microscopy; polyacrylamide; structural biology; tissue /cell culture; tissue support frame

DESCRIPTION (provided by applicant): At Rutgers University, in collaboration with Lucent Technology, we have embarked on the design of a new class of biomaterials from DMA crosslinked hydrogels that promises to have a wide rage of applications from drug delivery to prosthetics. Hybridization chemistry and strand displacement mechanisms based on branch migration allow these materials to be reversibly assembled and disassembled. Choice of base sequence allows for the design of gels that are degraded by particular restriction endonucleases or by particular messenger RNA strands. Altering the composition of the polymer, the length of the DNA strands, or the density of the crosslinks allows these materials to exhibit a wide range of mechanical properties. These gels are synthetic materials that exhibit tensegrity (prestress) and, thus, represent a novel class of biomimatic materials that may shed light on the mechanical basis of cell shape stability. Based on the success in our initial 3 years of research, here we propose to measure some of the more basic mechanical properties of polyacrylamide DNA-crosslinked gels. We will determine the elastic moduli and yield strengths, as a function of composition. In addition, we will map out the degree to which the compliance of such gels can be made modulated through the application of DNA strands. We will also map out the degree of prestress that can be built into such gels and determine how closely such gels can be made to mimic the mechanical properties of the cytoskeleton. DNA-crosslinked polyacrylamide gels provide an ideal framework for studying cell interactions with substrates of varying stiffness because the acrylamide chemistry enables easy attachment of the gel to glass. The stiffness is easily controlled by the amount of crosslinking DNA present, and stiffness gradients within the gel are possible by regulating the delivery of the crosslinking solution. Furthermore, thermo- and DNA-actuated reversibility of the gel provides attractive features for tissue engineering studies, since substrate rigidity has been found to regulate the transition of cells from mitogenic to functionally mature and may, in some cases, direct cell differentiation. We will investigate the use of these materials to alter the response of stem cells to the mechanical properties of their environment. In particular, the ability to change the mechanical properties of DNA-crosslinked gels, spatially and temporally, without changing temperature and/or the chemical composition of the buffer, should make DNA-crosslinked gels ideal for the investigation of embryonic stem migration and differentiation in response to gradients and temporal changes in the elastic moduli. We will carry out such studies using a murine embryonic cell line. These studies will also allow us to address issues of biocompatibility and the effect that embryonic stem cells might have on DNA crosslinks. Magnetic microneedles will be used to monitor the compliance properties of the gel during the course of the experiment. Our long-term goal is to create tissue engineered reversible dynamic three-dimensional scaffolds, which will comprise an acryl-based hydrogel that can be reversibly crosslinked with DNA strands to dynamically modulate its stiffness and apply force. Moreover, the biomaterial will also be functionalized with bioactive matrix molecules to support cell attachment, growth, and migration.

描述（由申请人提供）：在罗格斯大学，我们与朗讯科技公司合作，开始利用 DMA 交联水凝胶设计一类新型生物材料，该材料有望在从药物输送到假肢等领域具有广泛的应用。基于分支迁移的杂交化学和链置换机制允许这些材料可逆地组装和拆卸。碱基序列的选择允许设计可被特定限制性核酸内切酶或特定信使RNA链降解的凝胶。改变聚合物的组成、DNA 链的长度或交联的密度可以使这些材料表现出广泛的机械性能。这些凝胶是表现出张拉整体性（预应力）的合成材料，因此代表了一类新型仿生材料，可以揭示细胞形状稳定性的机械基础。基于我们最初 3 年研究的成功，我们建议测量聚丙烯酰胺 DNA 交联凝胶的一些更基本的机械性能。我们将确定弹性模量和屈服强度，作为成分的函数。此外，我们将确定通过应用 DNA 链可以调节此类凝胶的顺应性的程度。我们还将绘制出可内置于此类凝胶中的预应力程度，并确定此类凝胶可以在多大程度上模拟细胞骨架的机械特性。 DNA 交联聚丙烯酰胺凝胶为研究细胞与不同硬度基质的相互作用提供了理想的框架，因为丙烯酰胺化学性质使凝胶能够轻松附着在玻璃上。硬度很容易通过存在的交联 DNA 的量来控制，并且通过调节交联溶液的输送可以实现凝胶内的硬度梯度。此外，凝胶的热驱动和 DNA 驱动的可逆性为组织工程研究提供了有吸引力的特征，因为已发现基质刚性可以调节细胞从有丝分裂到功能成熟的转变，并且在某些情况下可能指导细胞分化。我们将研究使用这些材料来改变干细胞对其环境机械特性的反应。特别是，在不改变温度和/或缓冲液化学成分的情况下，在空间和时间上改变DNA交联凝胶的机械特性的能力，应该使DNA交联凝胶成为研究胚胎干迁移和分化的理想选择。对弹性模量的梯度和时间变化的响应。我们将使用鼠胚胎细胞系进行此类研究。这些研究还将使我们能够解决生物相容性问题以及胚胎干细胞可能对 DNA 交联产生的影响。磁性微针将用于在实验过程中监测凝胶的顺应性。我们的长期目标是创建组织工程可逆动态三维支架，该支架将包含基于丙烯酸的水凝胶，可以与 DNA 链可逆交联，以动态调节其刚度和施加力。此外，生物材料还将用生物活性基质分子进行功能化，以支持细胞附着、生长和迁移。