Chaotic synchronization of surface chemistry and vesicular assembly in hydrothermal microenvironments

德克萨斯农工大学的Victor Ugaz和Yassin Hassan得到了化学系生命过程化学项目的支持，以了解在微尺度、模拟气孔的环境中热对流、混沌混合和表面化学反应动力学之间的相互作用。化学、生物工程、环境和运输系统(CBET)分部的细胞和生化工程项目也为该奖项做出了贡献。一个悬而未决的问题是，长链分子是如何从基本构件中最先合成的。渗透水下热液喷口附近矿物层的孔隙网络，例如最近在失落的城市和大西洋中部山脊发现的孔洞网络，已经成为地球和其他地方此类生化过程的潜在热点。然而，详细的合成机理尚不清楚，因为周围海水中前体化合物的浓度太低，无法引发聚合。乌加兹和哈桑的研究正在探索一种新的传输过程--混沌热对流--这是在热液微环境中自然产生的。这一过程不断地将分子前体从主体流体穿梭到催化活性固体边界上的目标位置。研究人员正在定量绘制通过这一过程可以实现的生物分子物种的富集图，利用一个新的实验平台来探索它对微孔环境中表面反应动力学的影响。这项研究还在探索利用这种运输机制来协调大分子物种组装成原始细胞样泡泡体，包装长链分子并保持局部的pH梯度。这种原细胞的设计和构建可以提供对细胞功能的有价值的见解，并在生物制造的生物合成反应系统的设计中具有实际应用。该项目正在通过创新的实践模块加强学生的教育和培训，以设计、建造和操作代表生命起源的益生菌热液情景和关键物理化学过程的微型对流反应堆。配套的计算模块通过联合讲座和计算机实验室，将对流流动的实际模拟(使用熔岩灯作为相关的例子)与生化反应动力学相结合。乌加兹教授和哈桑教授正在进行协调的实验和模拟，以了解微尺度混沌热对流如何协同地促进整体化学物种的混合，同时加速在微流控反应器中离散位置的浓缩和泡状原细胞的组装和包装。一个耦合的三维计算流动和反应模型正在开发中，以量化主体流动特性如何控制表面反应和泡囊组装动力学。这一框架正被用来确定混沌在调节靶向浓缩方面的作用，以及确定有利于加速表面反应和原细胞形成的热和几何条件的范围。这些结果为阐明在具有代表性的海底热液网络条件下，混沌热对流调节大分子物种的组装及其在原细胞中的封装的能力奠定了基础。从这些研究中获得的知识和见解正在提供对可能的途径的更深层次的理解，通过这些途径，代谢和复制系统的必要前体可以在地球和其他地方自发地出现。生物化学以外的重要过程也在水热微环境中被催化，这表明热对流现象在控制二氧化碳的运输和反应方面发挥了引人注目的作用。微尺度对流概念的简单性和相关性为创新的实践教学体验奠定了基础，这些体验指导学生完成代表热液活动的微尺度对流反应堆的设计、建造和操作过程。该奖项反映了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。

Victor Ugaz and Yassin Hassan of Texas A&M University are supported by the Chemistry of Life Processes Program in the Division of Chemistry to understand the interplay between thermal convection, chaotic mixing, and surface chemical reaction kinetics in microscale, pore-mimicking surroundings. The Cellular and Biochemical Engineering Program in the Division of Chemical, Bioengineering, Environmental, and Transport Systems (CBET) also contributes to this award. An unanswered question is how long-chain molecules were first synthesized from elementary building blocks. Pore networks permeating mineral formations near underwater hydrothermal vents such as those discovered recently in the Lost City and Mid-Atlantic Ridge have emerged as potential hot spots for such biochemical processes, both on Earth and elsewhere. However, the detailed synthesis mechanism remains unclear, because concentrations of the precursor compounds in the surrounding ocean waters would have been too dilute to initiate polymerization. Ugaz and Hassan's research is exploring a new transport process-chaotic thermal convection-that naturally arises in hydrothermal microenvironments. This process continually shuttles molecular precursors from the bulk fluid to targeted locations on catalytically-active solid boundaries. The investigators are quantitatively mapping the enrichment of biomolecular species that can be achieved via this process, utilizing a new experimental platform to probe its influence on surface reaction kinetics within microscale pore surroundings. The research is also exploring the use of this transport mechanism to orchestrate the assembly of macromolecular species into protocell-like vesicular bodies, to package long-chain molecules and maintain localized pH gradients. The design and construction of such protocells can provide valuable insight into cellular function, and has practical application to the design of biosynthetic reaction systems for biomanufacturing. The project is enhancing student education and training through innovative hands-on modules to design, build, and operate microscale convective reactors representative of prebiotic hydrothermal scenarios and key physicochemical processes central to the origin of life. Companion computational modules integrate practical simulations of convective flow (using lava lamps as a relatable example) with biochemical reaction kinetics, through combined lectures and computer labs.Professors Ugaz and Hassan are performing coordinated experiments and simulations to understand how microscale chaotic thermal convection synergistically promotes mixing of chemical species in the bulk, while simultaneously accelerating enrichment and vesicular protocell assembly and packaging at discrete locations in a microfluidic reactor. A coupled 3D computational flow and reaction model is being developed to quantify how bulk flow characteristics govern surface reaction and vesicular assembly kinetics. This framework is being applied to identify the role of chaos in mediating targeted enrichment, and in defining the range of thermal and geometric conditions conducive to accelerated surface reactions and protocell formation. These results are laying the foundation to elucidate the ability of chaotic thermal convection to mediate assembly of macromolecular species and their encapsulation in protocells, under conditions representative of subsea hydrothermal networks. The knowledge and insights gained from these studies are providing a deeper understanding of possible pathways through which the necessary precursors to metabolic and replicating systems can spontaneously emerge, both on Earth and elsewhere. Important processes beyond biochemistry are also catalyzed in hydrothermal microenvironments, suggesting a compelling role for thermal convective phenomena in governing the transport and reaction of carbon dioxide. The conceptual simplicity and relatability of microscale convective flows is providing the foundation for innovative hands-on educational experiences that guide students through the process of designing, building, and operating microscale convective reactors representative of hydrothermal activity.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.