Thermodynamics of Growing Active and Living Matter

活性物质和生命物质生长的热力学

• 批准号: EP/W027194/1
• 负责人: Elsen Tjhung
• 金额: $ 128.66万
• 依托单位: The Open University
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW027194%2F1
• 关键词: Thermodynamics; Growing; Active; Living; Matter

When we learnt classical thermodynamics from undergraduate physics/chemistry, we often assumed a large number of particles ~10^23, equilibrium, and quasi-static process. In this very restrictive limit, thermodynamic quantities such as heat dissipation Q, can be computed using the textbook formula Q= T\Delta S, where S is the configurational entropy. However, in real lives, most physical processes are neither quasi-static nor equilibrium. Furthermore, in many biological systems, the number of degrees of freedom is also much less than 10^23, and in this regime, thermal fluctuations become important. Thus, thermodynamic quantities such as heat, work and entropy need to be redefined properly (Stochastic Thermodynamics). The first aim of this research is to extend the theory of stochastic thermodynamics to include birth and death process, e.g., cellular division and apoptosis in living tissues and growing bacterial colonies.One important application of stochastic thermodynamics is the prospects of biological machines, which are powered by the swimming motility in some bacteria, or even cellular division and apoptosis in our bodies. For instance, it has been well known experimentally and theoretically that if we place an asymmetric cog inside a bath full of swimming bacteria, the cog can somehow rotate persistently in one direction. The bacteria themselves, in the absence of the cog, swim in a completely random direction; and yet the interaction between the bacteria and the asymmetric cog can break time reversal symmetry to create a macroscopic unidirectional current. Although this phenomenon has been well established in motile active matter (such as swimming bacteria), very little is known about non-motile growing active matter (such as cell division and apoptosis in living tissues and bacterial colonies).In this research, I will explore cellular division and apoptosis as a new route to the development of biological machines. This is important because unlike cell motility, cell division and apoptosis are universal properties of living matter. My design principles for such machines will pave the way for future possible applications in healthcare technologies and tissue engineering, such controlling the growth of tissue using non-uniform scaffolding.Finally, I will investigate the thermodynamic properties of these machines. In particular, I will quantify the informatic entropy production of the birth and death process inside biological tissues and bacterial colonies, i.e., particles dividing into two and disappearing elsewhere. To achieve this, I will extend the current theory of stochastic thermodynamics to include birth and death process and stochastic processes that are much faster than quasi-static (i.e., quenching). This information will be crucial in understanding how time reversal symmetry breaking at small scales (i.e., cell cycle) can be translated into large scales (i.e., collective motion in tissues and bacterial colonies). Apart from obvious applications to active/living matter, my research will also help to transform the science of thermodynamics, such as understanding the energy flow in a quenching process and/or processes close to a critical point, where thermal fluctuations are important.

当我们从本科物理/化学中学到经典的热力学时，我们经常假设大量颗粒〜10^23，平衡和准静态过程。在这个非常限制的极限中，可以使用教科书公式q = t \ delta s来计算热力学数量，例如散热Q，其中S是配置熵。但是，在现实生活中，大多数物理过程既不是准静态的也不是平衡。此外，在许多生物系统中，自由度的数量也远远小于10^23，在这种制度中，热波动变得很重要。因此，需要正确重新定义热力学数量，例如热量，工作和熵（随机热力学）。这项研究的第一个目的是将随机热力学的理论扩展到包括出生和死亡过程，例如在活组织中的细胞分裂和细胞凋亡以及生长的细菌菌落。随机热力学的重要应用是生物学机器的前景，是生物机器的前景由某些细菌的游泳运动能力，甚至在我们体内的细胞分裂和凋亡。例如，从实验和理论上众所周知，如果我们将一个不对称的齿轮放在装满游泳细菌的浴缸内，则齿轮可以以某种方式沿一个方向持续旋转。细菌本身在没有齿轮的情况下，沿完全随机的方向游泳。然而，细菌与不对称COG之间的相互作用会破坏时间逆转对称性，从而产生宏观的单向电流。尽管这种现象已经在运动活性物质（例如游泳细菌）中得到了很好的确定，但对于非运动生长的活性物质（例如活性组织和细菌菌落中的细胞分裂和细胞凋亡）知之甚少。在这项研究中，我将探索细胞分裂和凋亡，作为生物机器发展的新途径。这很重要，因为与细胞运动不同，细胞分裂和凋亡是生物的普遍特性。我对此类机器的设计原理将为未来在医疗保健技术和组织工程中的应用铺平道路，例如使用非均匀的脚手架来控制组织的生长。在本文中，我将研究这些机器的热力学特性。特别是，我将量化生物组织和细菌菌落内的出生和死亡过程的信息熵产生，即分为两个并消失在其他地方的颗粒。为了实现这一目标，我将将当前的随机热力学理论扩展到包括出生和死亡过程以及比准静态速度快得多的随机过程（即淬灭）。这些信息对于了解时间逆转对称性如何在小尺度（即细胞周期）中破裂至关重要，可以转化为较大的尺度（即组织和细菌菌落中的集体运动）。除了明显的应用到活动/生活物质外，我的研究还将有助于改变热力学的科学，例如在淬火过程和/或靠近临界点的过程中了解热波动很重要的能量流。