3B´s Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal. ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal. Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Republic of Korea.
Biomed Mater. 2018 Apr 11;13(4):044101. doi: 10.1088/1748-605X/aab2fe.
The assembly of natural proteinaceous biopolymers into macro-scale architectures is of great importance in synthetic biology, soft-material science and regenerative therapy. The self-assembly of protein tends to be limited due to anisotropic interactions among protein molecules, poor solubility and stability. Here, we introduce a unique platform to self-immobilize diverse proteins (fibrous and globular, positively and negatively charged, low and high molecular weight) using silicon surfaces with pendant -NH groups via a facile one step diffusion limited aggregation (DLA) method. All the experimental proteins (type I collagen, bovine serum albumin and cytochrome C) self-assemble into seaweed-like branched dendritic architectures via classical DLA in the absence of any electrolytes. The notable differences in branching architectures are due to dissimilarities in protein colloidal sub-units, which is typical for each protein type, along with the heterogeneous distribution of surface -NH groups. Fractal analysis of assembled structures is used to explain the underlying route of fractal deposition; which concludes how proteins with different functionality can yield similar assembly. Further, the nano-micro-structured surfaces can be used to provide functional topographical cues to study cellular responses, as demonstrated using rat bone marrow stem cells. The results indicate that the immobilization of proteins via DLA does not affect functionality, instead serving as topographical cues to guide cell morphology. This indicates a promising design strategy at the tissue-material interface and is anticipated to guide future surface modifications. A cost-effective standard templating strategy is therefore proposed for fundamental and applied particle aggregation studies, which can be used at multiple length scales for biomaterial design and surface reformation.
天然蛋白生物聚合物组装成宏观结构在合成生物学、软物质科学和再生治疗中具有重要意义。由于蛋白质分子之间的各向异性相互作用、较差的溶解性和稳定性，蛋白质的自组装往往受到限制。在这里，我们引入了一种独特的平台，通过简单的一步扩散限制聚集（DLA）方法，使用带有悬挂 -NH 基团的硅表面自固定各种蛋白质（纤维状和球状、带正电荷和带负电荷、低分子量和高分子量）。所有实验蛋白质（I 型胶原蛋白、牛血清白蛋白和细胞色素 C）在没有任何电解质的情况下通过经典的 DLA 自组装成海藻状分支树突状结构。由于每个蛋白质类型的胶体亚单位的差异，以及表面 -NH 基团的不均匀分布，导致分支结构的显著差异。分形分析用于解释分形沉积的潜在途径；该分析表明，具有不同功能的蛋白质可以产生相似的组装。此外，纳米微结构化表面可用作提供功能形貌线索的研究细胞反应的工具，如使用大鼠骨髓干细胞进行的研究。结果表明，通过 DLA 固定蛋白质不会影响其功能，而是作为指导细胞形态的形貌线索。这表明在组织-材料界面具有有前途的设计策略，并有望指导未来的表面修饰。因此，提出了一种具有成本效益的标准模板策略，用于基础和应用的粒子聚集研究，可用于多个长度尺度的生物材料设计和表面改造。
