Three-dimensional fibrillar networks reconstituted from collagen I are widely used as biomimetic scaffolds for in vitro and in vivo cell studies. Various physicochemical parameters of buffer conditions for in vitro fibril formation are well known, including pH–value, ion concentrations and temperature. However, there is a lack of a detailed understanding of reconstituting well-defined 3D network topologies, which is required to mimic specific properties of the native extracellular matrix. We screened a wide range of relevant physicochemical buffer conditions and characterized the topology of the reconstituted 3D networks in terms of mean pore size and fibril diameter. A congruent analysis of fibril formation kinetics by turbidimetry revealed the adjustment of the lateral growth phase of fibrils by buffer conditions to be key in the determination of pore size and fibril diameter of the networks. Although the kinetics of nucleation and linear growth phase were affected by buffer conditions as well, network topology was independent of those two growth phases. Overall, the results of our study provide necessary insights into how to engineer 3D collagen matrices with an independent control over topology parameters, in order to mimic in vivo tissues in in vitro experiments and tissue engineering applications.

Statement of Significance

The study reports a comprehensive analysis of physicochemical conditions of buffer solutions to reconstitute defined 3D collagen I matrices. By a combined analysis of network topology, i.e., pore size and fibril diameter, and the kinetics of fibril formation we can reveal the dependence of 3D network topology on buffer conditions, such as pH-value, phosphate concentration and sodium chloride content. With those results we are now able to provide engineering strategies to independently tune the topology parameters of widely used 3D collagen scaffolds based on the buffer conditions. By that, we enable the straightforward mimicking of extracellular matrices of in vivo tissues for in vitro cell culture experiments and tissue engineering applications.

中文翻译：

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原纤维生长动力学联系了3D胶原I网络的缓冲条件和拓扑

由胶原蛋白I重构的三维原纤维网络被广泛用作体外和体内细胞研究的仿生支架。体外缓冲条件的各种理化参数原纤维形成是众所周知的，包括pH值，离子浓度和温度。但是，缺少对重新定义明确的3D网络拓扑的详细了解，而这是模拟天然细胞外基质的特定属性所必需的。我们筛选了各种相关的理化缓冲条件，并根据平均孔径和原纤维直径表征了重构的3D网络的拓扑。通过比浊法对原纤维形成动力学的一致分析显示，通过缓冲条件调节原纤维的侧向生长相对于确定网络的孔径和原纤维直径是关键。尽管成核动力学和线性生长期也受缓冲液条件的影响，但网络拓扑结构与这两个生长期无关。体内组织在体外实验和组织工程中的应用。

重要声明

该研究报告对缓冲液的物理化学条件进行了全面分析，以重构定义的3D胶原I基质。通过对网络拓扑结构（即孔径和原纤维直径）以及原纤维形成动力学的综合分析，我们可以揭示3D网络拓扑结构对缓冲液条件（如pH值，磷酸盐浓度和氯化钠含量）的依赖性。通过这些结果，我们现在能够提供工程策略，以根据缓冲条件独立地调整广泛使用的3D胶原蛋白支架的拓扑参数。通过这种方式，我们可以直接模拟体内组织的细胞外基质，以用于体外细胞培养实验和组织工程应用。