Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Nat Mater. 2010 Nov;9(11):908-12. doi: 10.1038/nmat2854. Epub 2010 Oct 10.
Bilayer membranes envelope cells as well as organelles, and constitute the most ubiquitous biological material found in all branches of the phylogenetic tree. Cell membrane rupture is an important biological process, and substantial rupture rates are found in skeletal and cardiac muscle cells under a mechanical load. Rupture can also be induced by processes such as cell death, and active cell membrane repair mechanisms are essential to preserve cell integrity. Pore formation in cell membranes is also at the heart of many biomedical applications such as in drug, gene and short interfering RNA delivery. Membrane rupture dynamics has been studied in bilayer vesicles under tensile stress, which consistently produce circular pores. We observed very different rupture mechanics in bilayer membranes spreading on solid supports: in one instance fingering instabilities were seen resulting in floral-like pores and in another, the rupture proceeded in a series of rapid avalanches causing fractal membrane fragmentation. The intermittent character of rupture evolution and the broad distribution in avalanche sizes is consistent with crackling-noise dynamics. Such noisy dynamics appear in fracture of solid disordered materials, in dislocation avalanches in plastic deformations and domain wall magnetization avalanches. We also observed similar fractal rupture mechanics in spreading cell membranes.
双层膜包裹着细胞和细胞器，是在系统发生树的所有分支中发现的最普遍的生物材料。细胞膜破裂是一个重要的生物学过程，在机械负荷下，骨骼肌和心肌细胞的破裂率很高。破裂也可以由细胞死亡等过程诱导，而有效的细胞膜修复机制对于保持细胞完整性至关重要。细胞膜中的孔形成也是许多生物医学应用的核心，如药物、基因和短干扰 RNA 的传递。在拉伸应力下，双层囊泡中的膜破裂动力学已经得到了研究，这种囊泡通常会产生圆形孔。我们在在固体支撑物上扩展的双层膜中观察到非常不同的破裂力学：在一种情况下，会出现指状不稳定性，导致花状孔；而在另一种情况下，破裂会以一系列快速的雪崩形式进行，导致分形膜碎片。破裂演化的间歇性特征和雪崩大小的广泛分布与噼啪噪声动力学一致。这种噪声动力学出现在固体无序材料的断裂、塑性变形中的位错雪崩和畴壁磁化雪崩中。我们也在扩展的细胞膜中观察到类似的分形破裂力学。
