两个静态变形球体的配体介导黏附力学
Ligand-mediated adhesive mechanics of two static, deformed spheres.
作者信息
Sircar Sarthok, Nguyen Giang, Kotousov Andrei, Roberts Anthony J
机构信息
School of Mathematical Sciences, University of Adelaide, SA 5005, Adelaide, Australia.
School of Civil, Environmental and Mining Engineering, University of Adelaide, SA 5005, Adelaide, Australia.
出版信息
Eur Phys J E Soft Matter. 2016 Oct;39(10):95. doi: 10.1140/epje/i2016-16095-4. Epub 2016 Oct 24.
A self-consistent model is developed to investigate attachment/detachment kinetics of two static, deformable microspheres with irregular surface and coated with flexible binding ligands. The model highlights how the microscale binding kinetics of these ligands as well as the attractive/repulsive potential of the charged surface affects the macroscale static deformed configuration of the spheres. It is shown that in the limit of smooth, neutrally charged surface (i.e., the dimensionless inverse Debye length, [Formula: see text]), interacting via elastic binders (i.e., the dimensionless stiffness coefficient, [Formula: see text]) the adhesion mechanics approaches the regime of application of the JKR theory, and in this particular limit, the contact radius, R, scales with the particle radius, R, according to the scaling law, [Formula: see text]. We show that static, deformed, highly charged, ligand-coated surface of micro-spheres exhibit strong adhesion. Normal stress distribution within the contact area adjusts with the binder stiffness coefficient, from a maximum at the center to a maximum at the periphery of the region. Although reported in some in vitro experiments involving particle adhesion, until now a physical interpretation for this variation of the stress distribution for deformable, charged, ligand-coated microspheres is missing. Surface roughness results in a diminished adhesion with a distinct reduction in the pull-off force, larger separation gap, weaker normal stress and limited area of adhesion. These results are in agreement with the published experimental findings.
开发了一个自洽模型,以研究两个具有不规则表面且涂覆有柔性结合配体的静态可变形微球的附着/分离动力学。该模型突出了这些配体的微观尺度结合动力学以及带电表面的吸引/排斥势如何影响球体的宏观尺度静态变形构型。结果表明,在光滑、中性带电表面的极限情况下(即无量纲逆德拜长度,[公式:见正文]),通过弹性粘合剂相互作用(即无量纲刚度系数,[公式:见正文]),粘附力学趋近于JKR理论的应用范围,在这个特定极限下,接触半径R根据缩放定律[公式:见正文]与颗粒半径r成比例。我们表明,微球的静态、变形、高电荷、配体涂覆表面表现出很强的粘附力。接触区域内的法向应力分布随粘合剂刚度系数而调整,从区域中心的最大值到区域周边的最大值。尽管在一些涉及颗粒粘附的体外实验中有所报道,但到目前为止,对于可变形、带电、配体涂覆的微球应力分布的这种变化缺乏物理解释。表面粗糙度导致粘附力减弱,拉脱力明显降低、分离间隙增大、法向应力减弱以及粘附面积有限。这些结果与已发表的实验结果一致。