Barai Pallab, Kumar Aloke, Mukherjee Partha P
Department of Mechanical Engineering, Texas A&M University, College Station, Texas, United States of America.
Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.
PLoS One. 2016 Nov 2;11(11):e0165593. doi: 10.1371/journal.pone.0165593. eCollection 2016.
Formation of bacterial colonies as biofilm on the surface/interface of various objects has the potential to impact not only human health and disease but also energy and environmental considerations. Biofilms can be regarded as soft materials, and comprehension of their shear response to external forces is a key element to the fundamental understanding. A mesoscale model has been presented in this article based on digitization of a biofilm microstructure. Its response under externally applied shear load is analyzed. Strain stiffening type behavior is readily observed under high strain loads due to the unfolding of chains within soft polymeric substrate. Sustained shear loading of the biofilm network results in strain localization along the diagonal direction. Rupture of the soft polymeric matrix can potentially reduce the intercellular interaction between the bacterial cells. Evolution of stiffness within the biofilm network under shear reveals two regimes: a) initial increase in stiffness due to strain stiffening of polymer matrix, and b) eventual reduction in stiffness because of tear in polymeric substrate.
细菌在各种物体表面/界面形成生物膜菌落，不仅有可能影响人类健康和疾病，还会对能源和环境方面产生影响。生物膜可被视为软材料，理解其对外力的剪切响应是深入理解的关键要素。本文基于生物膜微观结构的数字化提出了一个中尺度模型，并分析了其在外部施加剪切载荷下的响应。在高应变载荷下，由于软聚合物基质内链的展开，很容易观察到应变强化型行为。生物膜网络的持续剪切载荷会导致应变沿对角线方向局部化。软聚合物基质的破裂可能会减少细菌细胞之间的细胞间相互作用。生物膜网络在剪切作用下刚度的演变呈现出两种状态：a）由于聚合物基质的应变强化导致刚度最初增加，b）由于聚合物基质的撕裂最终导致刚度降低。
