Japan_IPAP: Embedding protein crystals within synthetic tissues as catalytic soft materials

自下而上的合成生物学旨在通过结合分子来模拟生物学中存在的结构、功能和包含信息的角色来重现细胞生物的结构和行为。这些结构被称为合成细胞，它们可以作为研究生物过程（如运动或复制）的框架，也可以作为微型试管，在其中可以进行化学和生化反应。从生物学中获得进一步的灵感，单个合成细胞的组装导致合成组织的产生，其中不同的隔室类型可以集成在一个更大的结构中，作为优化的微尺度反应容器，可以通过隔室之间的分子反应物交换来激活。由于合成细胞和组织是由分子部分构成的，因此这些系统的设计具有巨大的灵活性，这已被用于形成由脂质、聚合物和蛋白质基膜组成的隔室。一个明显较少探索的领域是在合成细胞和组织内封装新型生物催化剂结构。其中一种催化剂是多面蛋白晶体，它可以通过在细胞中表达晶体来嵌入共同生产的酶催化剂。这利用了多面蛋白晶体的高稳定性（在自然界中用于在外部环境中保护病毒衣壳）来制造持久的催化剂。在这里，我们建议使用微流体方法来组装合成组织，i)在组织的不同隔室中封装酶嵌入的多面体晶体，ii)具有水凝胶外壳以增加组织材料的耐久性。我们将在芯片上组装油乳化液液滴中的水，将晶体封装在这些液滴的水腔中，然后将水凝胶粘在乳化液周围，生产出可以在液体和空气中处理的毫微米级装置。然后，我们将测试这些组织的催化活性，目的是生产具有长催化寿命的坚固软材料，只需在含反应物的溶液中孵育即可使用。在合成组织内的反应物吸收和转化后，我们的目标是通过洗涤循环释放产物，建立下一个基于组织的催化循环。这项概念验证工作将展示混合组织模拟在催化中的潜力，并且该框架可以扩展到设计新的，结合生物和化学催化途径，目前由于催化剂中毒在一锅系统中是不可能的。为了实现这一目标，我们正在汇集英国和日本的世界领先的研究专业知识，以期汇集世界其他地方无法获得的专业知识：即Ces（合成细胞和微流体），Ueno（多尺度催化生物材料）和Abe（催化蛋白质晶体生物材料）。

Bottom-up synthetic biology aims to reproduce the structures and behaviours of cellular organisms by combining molecules that mimic the structural, functional and information containing roles present in biology. These structures are known as synthetic cells, and they can act as a framework to study biological processes (such as movement or replication), as well as act as miniature test-tubes, within which chemical and biochemical reactions can be carried out. Taking further inspiration from biology, the assembly of individual synthetic cells leads to the creation of synthetic tissues, where different compartment types can be integrated within a larger structure to act as optimised microscale reaction vessels, which can be activated through the exchange of molecular reactants between compartments.As synthetic cells and tissues are constructed from molecular parts, there is huge flexibility in the design of these systems, and this has been exploited to form compartments from lipids, polymers and protein-based membranes. One area that is significantly less explored is the encapsulation of novel biocatalysts structures within synthetic cells and tissues. One such catalyst are polyhedrin protein crystals, which can be used to embed co-produced enzyme catalysts via expression of crystals in cells. This exploits the high stability of polyhedrin crystals (used to protect viral capsids in the external environment in nature) to create long-lasting catalysts.Here, we propose to use microfluidic approaches to assembling synthetic tissues that i) encapsulate enzyme-embedded polyhedrin crystals within different compartments of the tissue and ii) possess a hydrogel shell to increase the durability of the tissue material. We will assemble water in oil emulsion droplets on-chip, encapsulating the crystals within the aqueous compartments of these droplets, before gelating the hydrogel around the emulsion to produce milliscale devices that can be handled in liquid and air. We will then test the catalytic activity of these tissues, with the aim of producing robust soft materials with long catalytic lifetime that can be used simply via incubation in reactant-containing solution. After reactant takeup and conversion within the synthetic tissue, we will aim to release product through washing cycles, setting up the next tissue-based catalysis cycle. This proof-of-concept work will demonstrate the potential for hybrid tissue mimics in catalysis, and this framework could be extended to design new, combined bio- and chemo-catalytic routes currently impossible in one-pot systems due to catalyst poisoning.In order to achieve this we are bringing together world leading research expertise in the UK and Japan with a view to bringing together expertise not available in concert elsewhere in the word: namely Ces (synthetic cells and microfluidics), Ueno (multiscale catalytic biomaterials) and Abe (catalytic protein crystal biomaterials).