CAREER: Bottlebrush polymers as gateways to multiresponsive structures

第1部分：非技术概述活细胞通过由跨膜蛋白组成的膜孔进行仔细调节的运输，控制什么进入它们，什么离开它们，跨膜蛋白起到守门人的作用。在这样做的过程中，细胞能够评估环境中发生的事情并做出相应的反应。受这一功能的启发，这个职业项目的目标是开发独特的策略，使响应的孔形成结构能够引入聚合泡囊中。具体地说，这项工作旨在使用管状大分子，即所谓的核壳瓶刷，来模拟跨膜蛋白的门控功能，并使一类新的材料能够对机械激活、光学刺激、酸度变化等做出反应。这些细胞状结构将有助于设计出多响应系统，最终可能能够模拟触觉、视觉和气味等感官。在这项研究成果的基础上，人们可以很容易地设想将类似的系统应用于靶向药物输送、传感以及高价值应用的有源过滤设备。在开展这些学术活动的同时，还将利用社区活动向公众，特别是代表人数较少的少数群体推广STEM教育。这些活动将包括超越艺术和科学的倡议，鼓励初出茅庐的小学科学家成为创造者，并为研究生提供成为明天科学/技术全球思考者和领导者的工具。第二部分：技术概述本研究的基本目标是理解引导块状线性和瓶刷(BB)两亲共聚物共同组装成生物启发的多响应聚合体的关键现象。为此，设计了一个综合和定向的策略，依赖于三个相互关联的目标：(I)两亲性三嵌段共聚物的结构评估(例如刚性、交错、侧链长度)，(Ii)了解两亲性线型和BB嵌段共聚物的共组装，以及(Iii)通过在膜中加入成孔BB三嵌段，利用诸如pH、光和机械力等刺激来赋予聚合体多刺激响应性。在BBS中可以控制的许多参数，通常是垂直的，如持久长度、嫁接长度和密度，使它们对这个项目特别有吸引力。这项工作旨在实现到目前为止尚未被探索的复杂聚合物结构的自组装以及它们与传统线性嵌段共聚物的共同组装。这项工作的更广泛的结果可以在模拟细胞过程的复杂的、隔间的聚合体的制造中实现，也可以在依赖按需释放货物的活性滤膜和/或靶向递送系统中实现。非政府组织还将开展若干活动，鼓励多样性，普遍促进STEM，并加强代表不足的少数群体的参与。这些活动将包括Maker会议和黑客松，以及通过利用刺激反应材料固有的视觉吸引力来融合艺术和科学。促进全球科学观和将主动学习纳入课程是这个职业项目的其他综合目标之一。这个奖项反映了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。

Part 1: Non-technical summaryLiving cells control what enters them and what leaves using carefully regulated transport across membrane pores made up of transmembrane proteins, which act as gatekeepers. In doing so, cells are able to assess what goes on in their environment and respond accordingly. Inspired by this function, the objective of this CAREER project is to develop unique strategies that enable the introduction of responsive pore-forming structures into polymeric vesicles. Specifically, the work aims to use tube-like macromolecules, known as core-shell bottlebrushes, to emulate the gating function of transmembrane proteins and enable a new class of materials that respond to mechanical activation, optical stimulation, changes in acidity, etc. These cell-like structures will help devise multiresponsive systems that may ultimately be capable of mimicking senses such as touch, sight, and smell. Building upon the results of this research endeavor, one can readily envision to use similar systems for applications such as targeted drug delivery, sensing, as well as active filtration devices for high-value applications. Concomitantly with these scholarly activities, community events will be used to promote STEM education to the general public and, particularly, underrepresented minorities. These activities will include initiatives that transcend the arts and sciences, encourage budding grade-school scientists to become makers, and provide graduate students with the tools to be scientific/technological global thinkers and leaders of tomorrow.Part 2: Technical summaryThe underlying goal of this research is to comprehend the crucial phenomena directing the co-assembly of blocky linear and bottlebrush (BB) amphiphilic copolymers towards the fabrication of bioinspired multiresponsive polymersomes. To this end, an integrative and directed strategy that relies on three connected aims was devised: (i) structural evaluation of amphiphilic triblock copolymers (e.g. stiffness, interdigitation, side-chain length), (ii) understanding of the co-assembly of amphiphilic linear and BB block copolymers, and (iii) bestowing of multi-stimuli-responsiveness to polymersomes by incorporating pore-forming BB triblocks in membranes using stimuli such as pH, light, and mechanical force. The numerous parameters that can be controlled in BBs, often orthogonally, such as persistence length, grafting length and density, make them especially alluring for this project. This work aims to bring about hitherto underexplored aspects of the self-assembly of complex polymeric architectures and their co-assembly with conventional linear block copolymers. The broader results of this work may be implemented in the fabrication of intricate, compartmentalized polymersomes that emulate cellular processes, but also in systems such active filtration membranes and/or targeted delivery systems that rely on on-demand cargo release. The PI will also implement several activities to encourage diversity and promote STEM universally and enhance participation of underrepresented minorities. These activities will include maker conferences and hackathons, as well as blending arts and sciences by exploiting the inherent visual appeal of stimuli-responsive materials. Promotions of global views of sciences and inclusion of active learning in curricula are amongst the other integrated objectives of this CAREER project..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.