The most abundant protein in the human body, collagen, is widely used in tissue culture and engineering applications, spanning from substrate functionalization to fibrillar architectures and three-dimensional constructs. Collagen piezoelectricity provides an opportunity to exploit electromechanical coupling in these applications, wherein an applied mechanical stress generates charge, which might influence ion screening, protein absorption, and cell response. In type I collagen, the polarization direction follows the fibril orientation. Thus, control of fibril orientation and size in a collagen film or membrane may provide control of the polarization, enabling the creation of regions of uniform polarization direction. Here, aligned substrate-supported type I collagen membranes having fibril sizes from ∼100–500 nm are deposited using different osmotic concentrations (90, 190, and 290 mOsm/kg, from low to high ionic strength) to investigate the correlation between fibril size and piezoelectric properties. Lateral piezoresponse force microscopy is used to show that regions of uniform polarization orientation, as determined through 2D correlation analysis, decrease with increasing fibril size.

中文翻译：

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I型胶原膜中极性排序的原纤维大小依赖性控制

人体内含量最丰富的蛋白质——胶原蛋白，广泛用于组织培养和工程应用，从底物功能化到纤维状结构和三维结构。胶原压电为在这些应用中利用机电耦合提供了机会，其中施加的机械应力会产生电荷，这可能会影响离子筛选、蛋白质吸收和细胞反应。在 I 型胶原蛋白中，极化方向遵循原纤维方向。因此，控制胶原膜或膜中的原纤维取向和大小可以控制极化，从而能够产生均匀极化方向的区域。这里，使用不同的渗透浓度（90、190 和 290 mOsm/kg，从低到高离子强度）沉积原纤维尺寸为 100-500 nm 的对齐基底支撑的 I 型胶原膜，以研究原纤维尺寸与压电之间的相关性特性。横向压电响应力显微镜用于显示均匀极化方向的区域，如通过 2D 相关分析确定的，随着原纤维尺寸的增加而减少。