CAREER: Actuating robots with actomyosin active gels

肌动蛋白和肌球蛋白的非技术性凝胶存在于几乎每一个哺乳动物细胞中。这些凝胶能够施加收缩力量，允许细胞移动、分裂和改变形状。虽然众所周知，这些凝胶消耗化学能量并施加机械动力，但对能源消耗和动力消耗之间的关系还没有很好的了解。这项建议旨在通过同时测量能源消耗和机械功率来量化这种关系。这项工作将直接解决含有肌动蛋白和肌球蛋白的材料的耗能性质，这将阐明这些蛋白质如何使细胞和组织变形。此外，这项提议将开发肌动蛋白和肌球蛋白凝胶作为软机器人的执行器。这些机器人将利用肌动蛋白-肌球蛋白凝胶的动态性质在飞行中在最佳状态之间切换。此外，这项研究将启发一个教育机器人项目，该项目寻求建立一个由液体排出提供动力的机器人。技术摘要活性物质，包括细胞骨架蛋白肌动蛋白和肌球蛋白的活性凝胶，组成了一类令人着迷的系统，其中宏观现象产生于微观的化学能量消耗。这种能源消耗能否被利用来为机械任务提供动力？这个问题已经在可以旋转齿轮和驱动流动的活性流体的背景下进行了广泛的探索。最近，理论研究着眼于自推进粒子所做的功。然而，现有的研究还没有调查活性凝胶使其环境变形的情况。因此，细胞骨架肌球蛋白凝胶的机械功率输出仍然知之甚少。考虑到肌动蛋白细胞骨架在推动细胞和组织水平的变形中所起的核心作用，这个问题的存在令人惊讶。这一建议旨在通过同时测量能源消耗和机械功率来量化微观能源消耗和宏观电力消耗之间的关系。此外，这项提议将制定在各种软机器人应用中应用这种凝胶作为执行器的原则。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Abstract Gels of the proteins actin and myosin exist in virtually every mammalian cell. These gels are capable of exerting contraction forces, which allow cells to move, divide, and change shape. Although it is well known that these gels consume chemical energy and exert mechanical power, the relationship between energy consumption and power exertion is not well understood. This proposal aims to quantify this relationship by measuring both the energy consumption and mechanical power simultaneously. This work will directly address the energy-consuming nature of materials containing actin and myosin, which will elucidate how these proteins can deform cells and tissues. Furthermore, this proposal will develop gels of actin and myosin as actuators for soft robots. These robots will take advantage of the dynamic nature of actin-myosin gels to switch on-the-fly between optimal states. In addition, this research will inspire an educational robotics project that seeks to build a robot that is powered by the expulsion of a fluid. Technical Abstract Active matter, including active gels of the cytoskeletal proteins actin and myosin, comprises a fascinating class of systems wherein macroscopic phenomena emerge from a microscopic consumption of chemical energy. Can this energy consumption be harnessed to power mechanical tasks? This question has been extensively explored in the context of active fluids, which can rotate gears and drive flows. More recently, theoretical studies have looked at the work done by self-propelled particles. However, existing studies have not investigated cases where active gels deform their environment. Thus, the mechanical power output of cytoskeletal actomyosin gels remains poorly understood. The existence of this problem is surprising, considering the central role that the actomyosin cytoskeleton plays in driving deformations on cellular and tissue levels. This proposal aims to quantify the relationship between microscopic energy consumption and macroscopic power exertion by measuring both the energy consumption and mechanical power simultaneously. Furthermore, this proposal will develop the principles of applying such gels as actuators for various soft-robotics applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.