CAREER: Dissipative Non-Equilibrium Supramolecular Hydrogels Using Fuels

在自然界中发现的物质，包括构成人体细胞和组织的物质，其结构往往是短暂存在的，并依赖于某些刺激的存在。因此，用合成结构重建天然材料的瞬时、依赖于刺激的状态，提供了一种更精确地复制天然材料的工程方法，以追求更逼真的材料。该奖项旨在为瞬态材料的创造建立新的途径，这将为未来的功能结构和治疗设备的设计提供信息。具体地说，设想的材料的形成和稳定性是由持续消耗的燃料源的存在所决定的，其中材料的寿命是通过改变所施加燃料的剂量或改变材料暴露的环境条件来调节的。类似地，为了利用光作为燃料，设想了其他材料，将应用的光转化为指令线索，驱动具有可调寿命的瞬态材料形成。通过化学燃料或使用光来获取软材料的瞬态，为软材料的设计指明了一个新的方向，这些软材料具有基于自然模拟瞬态的增强功能，并在许多材料应用中得到了应用。整合在这一融合研究项目中的是一项正在进行的努力，旨在建立和扩大分子工程领域的实验室和课堂培训，以及通过研究、指导、社区外展和对化学和材料科学研究生的体验式培训来推进科学交流的实践。技术总结：自然界从存在于耗散非平衡态的物质中获得了显著的功能；只要看看细胞结构和运动就知道了，这是由atp驱动的肌动蛋白细胞骨架的非平衡组装引起的。因此，该职业奖将研究和培训结合起来，努力创造具有燃料依赖形成和瞬态稳定性的生物启发材料，并在燃料有限时随后消散。近年来，用合成类似物重建天然材料的耗散非平衡状态引起了许多人的关注。虽然以往的研究几乎都集中在依赖燃料的小分子组装上，但本文描述了一种依赖燃料的主-客体超分子水凝胶的非平衡形成的新范式。这一结果将通过识别基序来实现，这些基序依赖于可消耗的化学燃料源的持续供应，或者通过使用光响应基序来驱动光刺激改变基序的亲和力和/或动力学。当特定的化学或光燃料来源有限时，这些材料将短暂存在并消散到其设计的溶胶或弱凝胶的平衡状态。更广泛地说，主客体超分子识别提供了一类有用的软材料，其特性直接归因于其交联相互作用的动态性质。因此，这些材料在其作为新的生物材料和治疗递送装置的应用中表现出各种有用的新特性，并且还提供了许多工业应用所需的特性。进一步整合这类材料的瞬态和燃料依赖形成的能力寻求增加的仿生功能，以进一步扩大其可能的用途。该研究计划被放置在一个多学科的培训环境中，为培养分子工程融合学科的领导者而量身定制，并通过课堂教学进一步加强。此外，旨在改善化学和材料科学的科学传播的培训，力求实现更好的公众参与，传达科学研究的重要性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical SummaryMaterials found throughout nature, including those which compose the cells and tissues of the body, have structures that often exist transiently and are dependent on the presence of certain stimuli. Recreating the transient, stimuli-dependent states of natural materials with synthetic constructs thus offers an approach to more precisely engineer replicates of natural materials in pursuit of more life-like materials. This CAREER award seeks to establish new routes to the creation of transient materials which will inform the future design of functional constructs and therapeutic devices. Specifically, materials for which formation and stability is dictated by the presence of a continuously consumed fuel source are envisioned, wherein the lifetime of the material is tunable through altering the dosage of applied fuel or changing the environmental conditions to which the material is exposed. Similarly, toward harnessing light as a fuel, other materials are envisioned which convert applied light into a directive cue driving transient material formation with tunable lifetime. Accessing transient states in soft materials, by way of chemical fuels or by using light, points to a new direction in the design of soft materials with enhanced functionality rooted in their nature-mimetic transient states, with uses in advancing a number of material applications. Integrated within this convergent research program is an ongoing effort to build and expand laboratory and classroom training in the area of molecular engineering, and an overarching goal to advance the practice of scientific communication through research, mentorship, community outreach, and experiential training for graduate trainees in the chemical and materials sciences.Technical SummaryNature achieves remarkable function from materials which exist in dissipative non-equilibrium states; one must look no further than the cell structure and motility which arises from ATP-fueled non-equilibrium assembly of its actin cytoskeleton. Accordingly, this CAREER award integrates research and training in an effort to create bio-inspired materials with fuel-dependent formation and transient stability, and which subsequently dissipate when fuel is limited. Recreating the dissipative non-equilibrium states of natural materials with synthetic analogues has captivated many in recent years. While efforts have focused almost exclusively on fuel-dependent assembly of small molecules, a new paradigm is described here for fuel-dependent non-equilibrium formation of host–guest supramolecular hydrogels. This outcome will be achieved through recognition motifs which are dependent on a continuous supply of a consumable chemical fuel source, or by using light-responsive motifs to actuate a light stimulus into altered affinity and/or dynamics of the motif. When the specific chemical or light fuel sources are limited, these materials will exist transiently and dissipate to their designed equilibrium state of a sol or weak gel. More broadly, host–guest supramolecular recognition affords a useful class of soft materials which have properties directly attributed to the dynamic nature of their crosslinking interactions. These materials have thus exhibited a variety of useful emergent properties in their application as new biomaterials and therapeutic delivery devices, and also afford features desirable for a number of industrial applications. The ability to further integrate transient and fuel-dependent formation of this class of materials seeks increased biomimetic function to further expand on their possible uses. This research plan is placed within a multidisciplinary training environment tailored to train leaders in the convergent discipline of molecular engineering, which is further augmented by classroom instruction. In addition, training aimed at improving scientific communication in the chemical and materials sciences seeks to achieve improved public engagement conveying the importance of scientific research.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.