中科院科学家在淀粉样纤维的生物纳米材料研究取得新进展

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2015年6月23日讯 /生物谷BIOON/ --2015年6月1日，中国科学院生物物理研究所柯莎（Sarah Perrett）课题组在《ACS Nano》在线发表了题为“Enzymatically Active Microgels from Self-Assembling Protein Nanofibrils for Microflow Chemistry”的研究成果，介绍了该课题组发展的将蛋白淀粉样纤维应用为生物纳米材料的新方法。

淀粉样纤维是蛋白或多肽自发组装形成的一种高度有序的纤维状聚集体，不仅与哺乳动物的神经退行性疾病相关，而且也会参与生物体正常生理功能。而目前在该领域出现的挑战在于如何能够使这些淀粉样蛋白不经过外界的强刺激在温和条件下实现其自组装。多年来，柯莎课题组致力于研究淀粉样纤维的形成以及传播机制。同时，柯莎课题组也开展了淀粉样纤维作为生物材料的应用研究，因为淀粉样纤维作为一种由蛋白自发组装形成的有序聚集体，具有良好的稳定性和形态多样性，体现出良好的生物纳米材料特性。

微凝胶作为一种微米尺寸的三维网状胶体颗粒，具有独特而重要的应用价值。在生物医学领域，微凝胶可以被应用为药物的运输和缓释载体，也可以被制备成微型生物反应器，还可以被应用到组织修复中等。然而，目前对于微凝胶的制备，还主要集中于利用化学有机分子形成的高聚物，应用于生物医学领域时，难以克服生物相容性和可生物降解等问题。通常来讲，利用生物体内天然存在的大分子制备凝胶能够更好地模拟生物体条件或不引起强烈的免疫排斥。

在之前的研究中，柯莎组已经利用酵母淀粉样性质蛋白Ure2作为纳米骨架分子，实现了活性酶分子在淀粉纤维表面的高效固定化展示。基于此研究，柯莎组结合微流控技术，将融合有活性酶分子的Ure2蛋白制备成均一的微米液滴，通过蛋白在液滴内自发组装形成淀粉样纤维，制备出结构和性质良好的微凝胶，并具有相应生物酶活性。与传统的以化学有机分子为材料制备的微凝胶相比，蛋白微凝胶或具有更好的生物医学应用前景。（生物谷Bioon.com）

生物谷推荐的英文摘要：

ACS Nano   DOI: 10.1021/acsnano.5b00061

Enzymatically Active Microgels from Self-Assembling Protein Nanofibrils for Microflow Chemistry

Amyloid fibrils represent a generic class of protein structure associated with both pathological states and with naturally occurring functional materials. This class of protein nanostructure has recently also emerged as an excellent foundation for sophisticated functional biocompatible materials including scaffolds and carriers for biologically active molecules. Protein-based materials offer the potential advantage that additional functions can be directly incorporated via gene fusion producing a single chimeric polypeptide that will both self-assemble and display the desired activity. To succeed, a chimeric protein system must self-assemble without the need for harsh triggering conditions which would damage the appended functional protein molecule. However, the micrometer to nanoscale patterning and morphological control of protein-based nanomaterials has remained challenging. This study demonstrates a general approach for overcoming these limitations through the microfluidic generation of enzymatically active microgels that are stabilized by amyloid nanofibrils. The use of scaffolds formed from biomaterials that self-assemble under mild conditions enables the formation of catalytic microgels while maintaining the integrity of the encapsulated enzyme. The enzymatically active microgel particles show robust material properties and their porous architecture allows diffusion in and out of reactants and products. In combination with microfluidic droplet trapping approaches, enzymatically active microgels illustrate the potential of self-assembling materials for enzyme immobilization and recycling, and for biological flow-chemistry. These design principles can be adopted to create countless other bioactive amyloid-based materials with diverse functions.

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