Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences最新文献

A cell’s mechanical environment regulates biological activities. Several studies have investigated the response of healthy epithelial mammary (MCF10A) and breast cancer (MCF7) cells to vascular and interstitial fluid motion-induced hydrodynamic forces. The mechanical stiffness of healthy and breast cancer cells differ significantly, which can influence the transduction of forces regulating the cell’s invasive behaviour. This aspect has not been well explored in the literature. The present work investigates the mechanical response of MCF10A and MCF7 cells to tissue-level interstitial fluid flow. A two-dimensional fluid flow–cell interaction model is developed based on the actual shapes of the cells, acquired from experimental fluorescent images. The material properties of the cell compartments (cytoplasm and nucleus) were assigned in the model based on the literature. The outcomes indicate that healthy MCF10A cells experience higher von Mises and shear stresses than the MCF7 cells. In addition, the MCF7 cell experiences higher strain and displacements than its healthy counterpart. Thus, the different mechano-responsiveness of MCF10A and MCF7 cells could be responsible for regulating the invasive potential of the cells. This work enhances our understanding of mechanotransduction activities involved in cancer malignancy which can further help in cancer diagnosis based on cell mechanotype.

Quantifying the response of marine mussel plaque attachment to wet surfaces remains a significant challenge to a mechanistic understanding of plaque adhesion. Here, we develop a novel, customized microscope system, combined with two-dimensional in situ digital image correlation (DIC), to quantify the in-plane deformation of a deformable substrate that interacts with a mussel plaque under directional tension. By examining the strain field within the substrate, we acquired an understanding of the mechanism by which in-plane traction forces are transmitted from the mussel plaque to the underlying substrate. Finite-element (FE) models were developed to assist in the interpretation of the experimental measurement. Our study revealed a synergistic effect of pulling angle and substrate stiffness on plaque detachment, with mussel plaques anchoring to a ‘stiff’ substrate at small pulling angles, i.e. natural anchoring angles, having mechanical advantages with higher load-bearing capacity and less plaque deformation. We identify two distinct failure modes, i.e. shear-traction-governed failure (STGF) and normal-traction-governed failure (NTGF). It was found that increasing the stiffness of the substrate or reducing the pulling angle results in a change of the failure mode from NTGF to STGF. Our findings offer new insights into the mechanistic understanding of mussel plaque–substrate interaction, providing a plaque-inspired strategy to develop high-performance and artificial wet adhesion.

It is known that the widely studied Bray–Liebhafsky reaction typically exhibits complex chemical behaviour. Numerous mathematical systems have been proposed to describe the iodine oscillations that occur during this process. Recently, a four-variable model of the Bray–Liebhafsky reaction has been proposed and analytical and numerical investigations suggested that chaotic solutions may exist. We revisit this four-variable model here and perform what appears to be the first detailed work on this system. We suggest that this model is perhaps not chaotic after all. Informed by these fresh insights, we propose a reduced two-variable model based upon the four-variable system. This model is created with the twin goals of enabling simpler mathematical analysis while retaining the underlying chemical mechanisms. We are able to demonstrate that our reduced problem performs very well when compared with the full model for realistic parameter values. In particular, key regions of parameter space are identified within which temporal oscillations can occur. Moreover, these persistent oscillations are consistent with the available qualitative experimental observations.