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组合模拟生物学中存在的结构、功能和包含信息的角色的分子来再现细胞生物体的结构和行为。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物化学反应。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整合在更大的结构中，以充当优化的微尺度反应容器，其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建的，在这些系统的设计中存在巨大的灵活性，并且这已经被利用来由脂质、聚合物和基于蛋白质的膜形成隔室。一个领域，是显着较少探索的是新的生物催化剂结构内的合成细胞和组织的封装。一种这样的催化剂是多面体蛋白质晶体，其可用于通过在细胞中表达晶体来包埋共同产生的酶催化剂。这利用了多角体蛋白晶体的高稳定性（用于在自然界中保护外部环境中的病毒衣壳）来产生持久的催化剂。在这里，我们建议使用微流体方法来组装合成组织，i）将酶嵌入的多角体蛋白晶体封装在组织的不同隔室中，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包水乳液液滴，将晶体封装在这些液滴的水性隔室中，然后使乳液周围的水凝胶凝胶化，以生产可以在液体和空气中处理的毫米级设备。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的软材料，这些材料可以简单地通过在含有反应物的溶液中孵育来使用。在合成组织内的反应物吸收和转化之后，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物在催化方面的潜力，并且该框架可以扩展到设计新的，组合的生物和化学催化路线，目前由于催化剂中毒而无法在一锅系统中实现。为了实现这一目标，我们汇集了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没有的专业知识：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).