Tiribocchi Adriano, Durve Mihir, Lauricella Marco, Montessori Andrea, Succi Sauro
Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185 Rome, Italy.
Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161, Roma, Italy.
Soft Matter. 2023 Aug 30;19(34):6556-6568. doi: 10.1039/d3sm00561e.
We numerically study the dynamics of a passive fluid droplet confined within a microchannel whose walls are covered with a thin layer of active gel. The latter represents a fluid of extensile material modelling, for example, a suspension of cytoskeletal filaments and molecular motors. Our results show that the layer is capable of producing a spontaneous flow triggering a rectilinear motion of the passive droplet. For a hybrid design (a single wall covered by the active layer), at the steady state the droplet attains an elliptical shape, resulting from an asymmetric saw-toothed structure of the velocity field. In contrast, if the active gel covers both walls, the velocity field exhibits a fully symmetric pattern considerably mitigating morphological deformations. We further show that the structure of the spontaneous flow in the microchannel can be controlled by the anchoring conditions of the active gel at the wall. These findings are also confirmed by selected 3D simulations. Our results may stimulate further research addressed to design novel microfludic devices whose functioning relies on the collective properties of active gels.
我们对限制在微通道内的被动流体微滴的动力学进行了数值研究，该微通道的壁上覆盖着一层薄薄的活性凝胶。后者代表一种可拉伸材料的流体模型，例如，细胞骨架细丝和分子马达的悬浮液。我们的结果表明，该层能够产生自发流动，触发被动微滴的直线运动。对于混合设计（单个壁被活性层覆盖），在稳态下微滴呈现椭圆形，这是由速度场的不对称锯齿状结构导致的。相比之下，如果活性凝胶覆盖两壁，速度场呈现完全对称的模式，大大减轻了形态变形。我们进一步表明，微通道中自发流动的结构可以通过活性凝胶在壁上的锚定条件来控制。这些发现也得到了选定的三维模拟的证实。我们的结果可能会激发进一步的研究，旨在设计新型微流体装置，其功能依赖于活性凝胶的集体特性。
