Adaptive Microfluidic Networks for Optimal Transport

从动物的血管系统到真菌的菌丝网络，再到组成电池的随机多孔介质，复杂网络中的流动传输在生物学和工程学中都是非常丰富的。长期以来，人们一直认为，优化了生物网络的形态，以最大限度地减少与其分支中的粘性流动耗散相关的能量成本。然而，最近提出的另一种可能性是，这些网络对于质量交换或灌流是最佳的。然后，我们不仅需要一个有效覆盖空间的网络，而且需要其形态导致化学物质(催化剂、营养物质、氧气等)的均匀流动。通过它的所有管道，所以网络的所有部分都接收到相同数量的化学物质。生命系统不断地调整它们的网络形态以响应刺激；局部反馈与全局流的存在相结合，导致最适合灌流的自组织结构。相反，工程随机介质网络中的流体速度因管而异，并遵循总体指数分布。通过这些多孔介质的运输效率很低，仅限于几条快车道。目前在多孔介质中优化流动的策略是一个分支一个分支地构建优化的网络形态。我们项目的目的是结合理论、模拟和实验来生成自适应微流控网络，其形态根据信号自组织，从而产生最适合灌流的网络形态。除了其根本利益外，该项目的成果还有广泛的应用，从设计和冷却高效电池，到生产具有高运输效率和大反应表面的增强型化学反应堆，有助于拥有更清洁、更负担得起的能源。

Flow transport in complex networks is abundant in biology and engineering, from the vasculature of animals, to the hyphal networks of fungi, to the random porous media making up batteries. It has long been thought that biological network morphologies were optimised to minimise the energetic cost associated to viscous flow dissipation in their branches. However, another possibility, raised recently is for these networks to be optimal for mass exchange, or perfusion. We then need not only to have a network that covers space efficiently, but also whose morphology leads to an even flow of chemicals (catalysts, nutrients, oxygen,...) throughout all its tubes, so that all parts of the network receive the same amount of chemical. Living systems continuously adapt their network morphology in response to stimuli; local feedback coupled to the presence of global flows leads to self-organised structures optimal for perfusion. In contrast, fluid velocities in engineered networks of random media differ from tube to tube, and follow an overall exponential distribution. Transport through these porous media is inefficient, being limited to a few fast lanes. The current strategy to optimize flow in porous media is to build, branch by branch, an optimized network morphology. The aim of our project is to combine theory, simulations and experiments to generate adaptive microfluidic networks whose morphology self-organises in response to signals, leading to network morphologies optimal for perfusion. In addition to its fundamental interest, the outcome of this project has a wide range of applications, from the design and cooling of efficient batteries, to the production of enhanced chemical reactors having high transport efficiency and a large reaction surface, contributing to having a cleaner, more affordable energy.