Santos Tatiana P, Calabrese Vincenzo, Boehm Michael W, Baier Stefan K, Shen Amy Q
Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan.
Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan.
J Colloid Interface Sci. 2023 May 15;638:487-497. doi: 10.1016/j.jcis.2023.01.105. Epub 2023 Jan 27.
Protein nanofibrils (PNF) resulting from the self-assembly of proteins or peptides can present structural ordering triggered by numerous factors, including the shear flow. We hypothesize that i) depending on the contour length of the PNF and the magnitude of the shear rate applied to the PNF dispersion, they exhibit specific orientation, and ii) it is possible to predict the alignment of PNF by establishing a flow-alignment relationship. Understanding such a relationship is pivotal to improving the fundamental knowledge and application of fibril systems.
We use β-lactoglobulin PNF aqueous dispersions with different average contour lengths but equal persistence lengths. We employ simple shear-dominated microfluidic devices with state-of-the-art imaging techniques: flow-induced birefringence (FIB) and micro-particle image velocimetry (μ-PIV), to probe the effect of shear flow on PNF alignment.
We provide an empirical relationship connecting the birefringence Δn (quantifying the extent of PNF alignment), and the Péclet number Pe (correlating the shear rate of the flow relative to the rotational diffusion of PNF) to understand the flow-alignment behavior of PNF under shear-dominated flows. Furthermore, we assess the alignment and flow profile of PNF at both high and low flow rates. The length of PNF emerges as a controlling parameter capable of modulating PNF alignment at specific shear rates. Our results shed new insights into the hydrodynamic behavior of PNF, which is highly relevant to various industrial processes involving the fibril systems.
蛋白质或肽自组装形成的蛋白质纳米纤维（PNF）可呈现由多种因素触发的结构有序性，包括剪切流。我们假设：i）根据PNF的轮廓长度以及施加于PNF分散体的剪切速率大小，它们会呈现特定的取向；ii）通过建立流动取向关系能够预测PNF的排列。理解这种关系对于提升纤维系统的基础知识和应用至关重要。
我们使用具有不同平均轮廓长度但持久长度相等的β-乳球蛋白PNF水分散体。我们采用以简单剪切为主的微流控装置以及先进的成像技术：流动诱导双折射（FIB）和微粒图像测速技术（μ-PIV），来探究剪切流对PNF排列的影响。
我们提供了一种经验关系，将双折射Δn（量化PNF排列程度）和佩克莱数Pe（关联流动的剪切速率与PNF的旋转扩散）联系起来，以理解在以剪切为主的流动条件下PNF的流动取向行为。此外，我们评估了高低流速下PNF的排列和流动剖面。PNF的长度成为一个控制参数，能够在特定剪切速率下调节PNF的排列。我们的结果为PNF的流体动力学行为提供了新的见解，这与涉及纤维系统的各种工业过程高度相关。
