CAREER: Understanding bacteria encapsulation, proliferation and release in photodegradable hydrogel materials

摘要（非技术）微生物生物技术的进步继续扩大我们对细菌世界的了解。为了充分理解和预测细菌的行为，有必要将其分子组成与其可观察到的特征联系起来。这通常需要首先以高纯度分离单个细菌，这在目前很难做到。这个NSF CAREER奖的目标是研究使用光降解水凝胶材料来鉴定和分离具有独特功能的稀有细菌细胞进行分子分析。水凝胶是三维的水溶性聚合物，可用于封装细胞集合以供观察。首先将建立对水凝胶的化学和物理特性的基本理解，从而稳定和有效地包封细菌。然后，这些水凝胶将被设计为在暴露于对细菌无害的低能量近红外光下后降解，这将允许在任何时候从水凝胶中释放活的单细胞。其结果将是一种新的、基于材料的微生物分离方法，这种方法成本低，并且高度转化为标准微生物学实验室。这些水凝胶将在微生物学的其他新兴领域具有更广泛的应用，包括将治疗性细菌靶向递送到疾病部位。该项目的综合教育目标是通过联合微生物材料学者（JMMS）计划培养具有全球意识的学生，他们为材料科学和微生物学的跨学科研究职业做好了充分准备。JMMS平台将利用堪萨斯州立大学的既定项目，在整个堪萨斯州吸引和招募代表性不足的少数民族学生，并为学者提供国际研究经验。 该项目由NSF材料研究部的生物材料计划和刺激竞争研究的既定计划（EPSCoR）共同资助。摘要（技术）光降解水凝胶已被深入研究用于组织工程和靶向药物递送。然而，这些材料在很大程度上未被探索用于微生物学，但具有按需递送细菌以及用于低成本细胞分离方法的巨大潜力。这些能力对于推进我们对微生物世界的了解以及在新兴的治疗应用中使用细菌至关重要。该CAREER提案的总体目标是提供对水凝胶材料性质的基本理解，这些性质提供稳定的细菌包封、培养、运输和从具有高活力和精度的光降解水凝胶中释放。将确定使用硫醇-迈克尔加成反应将细菌包封到稳定的聚乙二醇基水凝胶中的逐步生长聚合，并研究水凝胶网孔尺寸和弹性对细菌增殖和运输的影响。上转换纳米颗粒将被整合到水凝胶基质中，以使用图案化的NIR光源研究单个细菌细胞的释放。最后，这些新材料将用于分离具有活的但不可培养的表型的稀有细菌，以进行后续分子分析。从这些任务中获得的知识将为水凝胶的合理设计提供信息，用于分离具有独特功能的单一细菌，用于基于“组学”的分析和将活的治疗性细菌递送到靶向疾病部位。该研究将通过联合微生物材料学者计划纳入教育计划，该计划是一个教育平台，旨在通过四个组成部分培养具有全球意识的跨学科学生：（1）与食品微生物学合作者的国际学生交流，（2）旨在吸引和招募整个堪萨斯州少数民族学生的外部外联机制，（3）使用跨学科指导探究教学方法的微生物材料课程，以及（4）公众参与。PI将利用堪萨斯州立大学的成功项目，以达到更广泛的受众，包括堪萨斯-路易斯斯托克斯少数民族参与联盟计划，项目影响，和科学自来水。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Abstract (non-technical)Advancements in microbial biotechnology continue to expand our knowledge of the bacterial world. To fully understand and predict behavior of bacteria, it is necessary to connect its molecular makeup with its observable characteristics. This often requires individual bacteria first be isolated at high purity, which is currently difficult to do. The goal of this NSF CAREER award is to investigate use of photodegradable hydrogel materials for identification and isolation of rare bacteria cells with unique function for molecular analysis. Hydrogels are three-dimensional, water-soluble polymers that can be used to encapsulate collections of cells for observation. A fundamental understanding of both chemical and physical characteristics of hydrogels that lead to stable and effective encapsulation of bacteria will first be established. These hydrogels will then be designed to degrade following exposure to low-energy, near-infrared light unharmful to bacteria, which will allow for release of live, single cells from the hydrogel at any time. The outcome will be a new, materials-based approach to microbial isolation that will be low cost and highly translational to the standard microbiology lab. These hydrogels will have broader application to other emerging areas in microbiology including targeted delivery of therapeutic bacteria to disease sites. The integrated educational goal of the project is to develop global-minded students who are well prepared for interdisciplinary research careers at the interface of materials science and microbiology through the Joint Microbe-Material Scholars (JMMS) program. The JMMS platform will leverage established programs at Kansas State University for engagement and recruitment of underrepresented minority students throughout the state of Kansas and will provide its scholars with international research experiences. This project is jointly funded by the Biomaterials Program of the NSF Division of Materials Research, and the Established Program to Stimulate Competitive Research (EPSCoR).Abstract (technical)Photodegradable hydrogels have been intensively studied for application in tissue engineering and targeted drug delivery. However, these materials are largely unexplored for use in microbiology, but have great potential for on-demand delivery of bacteria as well as for use in low-cost cell isolation methods. These capabilities are critical for advancing our knowledge of the microbial world and for using bacteria in emerging therapeutic applications. The overall goal of this CAREER proposal is to provide a fundamental understanding of hydrogel material properties that provide stable bacteria encapsulation, culture, transport, and release from photodegradable hydrogels with high viability and precision. Step-growth polymerizations that use thiol-Michael addition reactions for bacteria encapsulation into stable, polyethylene glycol-based hydrogels will be identified, and the impact of hydrogel mesh size and elasticity on bacteria proliferation and transport will be investigated. Up-conversion nanoparticles will be integrated into the hydrogel matrix to investigate release of individual bacteria cells using a patterned NIR light source. Finally, these novel materials will be tested for isolation of rare bacteria with viable but nonculturable phenotypes for follow-up molecular analysis. Knowledge gained from these tasks will inform the rational design of hydrogels for isolation of single bacteria with unique function for 'omics'-based analysis and delivery of live, therapeutic bacteria to targeted disease sites. The research will be integrated into the educational plan through the Joint Microbe-Material Scholars program, an educational platform designed to produce global-minded, interdisciplinary students through four components: (1) an international student exchange with collaborators in food microbiology, (2) an external outreach mechanism designed to engage and recruit minority students throughout the state of Kansas, (3) a microbe-material course that uses an interdisciplinary guided-inquiry teaching method, and (4) public engagement. The PI will leverage successful programs at Kansas State University for reaching broader audiences including the Kansas-Louis Stokes Alliance for Minority Participation program, Project IMPACT, and Science on Tap.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.