Aminocoatings for improving implants’ tissue integration: understanding underlying biological mechanisms

用于改善植入物组织整合的氨基涂层：了解潜在的生物学机制

• 批准号: 446225522
• 负责人: Professorin Dr. J. Barbara Nebe
• 金额: --
• 依托单位: Institut de Science des Matériaux de Mulhouse (IS2M)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/446225522?language=en
• 关键词: Aminocoatings; improving; implants; tissue; integration

Population aging in developed countries will further increase bone deficiencies due to pathologies such as osteoporosis. Thus, the need of bioactive implants with the capacity to integrate inside osteoporotic bone will raise significantly. Surface chemistry and topography modifications have been shown to improve bone implants tissue integration. In a recent common work using microfabricated surfaces, we demonstrated the predominance of chemistry versus topography in influencing bone cell response. Amine functionalization of geometrically grooved titanium substrates with poly(allylamine) plasma polymer was able to abrogate cell contact guidance along the microgrooves. This was the first demonstration of the possibility to overcome a strong topographical signal by changing the surface chemistry. Several hypotheses have been proposed to explain this effect: (a) the high electrostatic interactions that must occur between a negatively-charged cell membrane and the positively-charged amino residues; (b) the increased adsorption of cell-adhesive proteins from the serum with more efficient conformation for interaction with integrin receptors; (c) the capacity of polyamines residues released in medium to promote cell protrusion formation. However, this original result obtained by our two groups with poly(allylamine) plasma polymer coatings needs now to be analyzed more deeply to determine the role of physico-chemical surface properties on this cell behavior and the biological mechanisms involved. With the objective of determining the role of surface and/or volume density of amino groups in this cell response, we propose to develop controlled amino-rich nano-layers using three different techniques allowing increasing levels of control of chemical composition: (a) plasma polymerization of allylamine, (b) covalent grafting of polymer-based amino-rich nano-coatings with varying content in amino groups, and (c) self-assembled monolayers with amino terminal groups. On these perfectly characterized amino-rich organic surfaces, we will explore in depth which proteins from the serum are adsorbed on the surface, in which quantity and how they are conformed.To verify the adhesion and abrogation potential of these different surfaces in relationship with the density and organization of amino groups, the morphology of human bone cells will be evaluated in living and fixed cells on coated grooved substrates. The organization and dynamics of the cytoskeleton and focal adhesions will be quantified to implement an in silico cell model and determine the adhesion force and mechanical properties of cells adhering on amino-rich nano-layers. To go deeper into the analysis of the cellular mechanisms involved in cell response, both the signalling and the gene expression of the cells will be analyzed. The understanding of the mechanism of action of these amino-rich nano-layers shall bring basic knowledge essential for improving bioactive implants for deficient aged bone.

发达国家的人口老龄化将进一步加剧骨质疏松症等疾病引起的骨质缺乏。因此，对能够整合到骨质疏松骨内的生物活性植入物的需求将显着增加。表面化学和形貌修饰已被证明可以改善骨植入物的组织整合。在最近一项使用微加工表面的共同工作中，我们证明了化学与形貌在影响骨细胞反应方面的优势。用聚（烯丙胺）等离子体聚合物对几何凹槽钛基材进行胺官能化能够消除沿着微凹槽的细胞接触引导。这是通过改变表面化学来克服强地形信号的可能性的首次演示。已经提出了几种假设来解释这种效应：（a）带负电的细胞膜和带正电的氨基残基之间必然发生高静电相互作用； (b) 细胞粘附蛋白从血清中的吸附增加，具有与整联蛋白受体相互作用更有效的构象； (c)培养基中释放的多胺残基促进细胞突起形成的能力。然而，我们的两个小组使用聚（烯丙胺）等离子体聚合物涂层获得的原始结果现在需要进行更深入的分析，以确定物理化学表面特性对该细胞行为和所涉及的生物机制的作用。 为了确定氨基的表面和/或体积密度在这种细胞反应中的作用，我们建议使用三种不同的技术开发受控的富含氨基的纳米层，从而提高对化学成分的控制水平：（a）烯丙胺的等离子体聚合，（b）具有不同氨基含量的基于聚合物的富含氨基的纳米涂层的共价接枝，以及（c） 具有氨基末端基团的自组装单层。在这些完美表征的富含氨基的有机表面上，我们将深入探索血清中的哪些蛋白质被吸附在表面上、其数量以及它们如何整合。为了验证这些不同表面的粘附和消除潜力与氨基密度和组织的关系，将在涂层凹槽基质上的活细胞和固定细胞中评估人骨细胞的形态。细胞骨架和粘着斑的组织和动力学将被量化，以实现计算机细胞模型，并确定粘附在富含氨基的纳米层上的细胞的粘附力和机械特性。为了更深入地分析细胞反应所涉及的细胞机制，将分析细胞的信号传导和基因表达。了解这些富含氨基的纳米层的作用机制将为改善老化骨骼缺陷的生物活性植入物提供必要的基础知识。