标题： 自我辅助的变形虫状导航在复杂环境中的应用 显示英文标题

标题： Self-assisted Amoeboid Navigation in Complex Environments

摘要： 背景：许多类型的活细胞需要对外部刺激做出反应以完成其功能任务；这些任务包括伤口愈合、免疫反应和受精。 虽然方向性运动通常由外部信号决定，但实际的运动也受到物理限制，例如其他细胞和细胞外基质的存在。 在存在障碍物的情况下成功导航的能力不仅对生物体至关重要，而且可能在自主机器人运动的研究中具有相关性。 方法/主要发现：我们研究了在不同条件下阿米巴样趋化导航的计算模型，从无障碍环境中的运动到在障碍物之间导航，最后到在迷宫中移动。 我们将迷宫作为严重约束运动任务的简单替代，这可能在致密的细胞外基质中出现。 尽管使用简单趋化性的代理可以成功绕过小障碍物，但大型障碍物的存在常常导致代理被困。 我们进一步表明，采用一种简单的记忆机制，即代理分泌一种排斥性化学物质，有助于代理摆脱这种困境。 结论/重要性：我们的主要结论是，采用简单趋化策略的细胞通常无法通过类似迷宫的几何结构，但一种简单的化学标记机制（我们称之为“自我协助”）显著提高了成功率。 这一认识为真实细胞在复杂环境中迁移可能采用的机制提供了重要的见解，也为机器人导航策略的设计提供了线索。 结果可以扩展到更复杂的多细胞系统，并可用于哺乳动物细胞迁移和癌症转移的研究。 显示英文摘要

摘要： Background: Living cells of many types need to move in response to external stimuli in order to accomplish their functional tasks; these tasks range from wound healing to immune response to fertilization. While the directional motion is typically dictated by an external signal, the actual motility is also restricted by physical constraints, such as the presence of other cells and the extracellular matrix. The ability to successfully navigate in the presence of obstacles is not only essential for organisms, but might prove relevant in the study of autonomous robotic motion. Methodology/principal findings: We study a computational model of amoeboid chemotactic navigation under differing conditions, from motion in an obstacle-free environment to navigation between obstacles and finally to moving in a maze. We use the maze as a simple stand-in for a motion task with severe constraints, as might be expected in dense extracellular matrix. Whereas agents using simple chemotaxis can successfully navigate around small obstacles, the presence of large barriers can often lead to agent trapping. We further show that employing a simple memory mechanism, namely secretion of a repulsive chemical by the agent, helps the agent escape from such trapping. Conclusions/significance: Our main conclusion is that cells employing simple chemotactic strategies will often be unable to navigate through maze-like geometries, but a simple chemical marker mechanism (which we refer to as "self-assistance") significantly improves success rates. This realization provides important insights into mechanisms that might be employed by real cells migrating in complex environments as well as clues for the design of robotic navigation strategies. The results can be extended to more complicated multi-cellular systems and can be used in the study of mammalian cell migration and cancer metastasis.