CAREER: Dissipative Non-Equilibrium Supramolecular Hydrogels Using Fuels

在自然界中发现的材料，包括那些组成人体细胞和组织的材料，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短暂的、依赖刺激的状态提供了一种方法，可以更精确地设计天然材料的复制品，以追求更像生命的材料。这个职业奖旨在建立新的路线，创造瞬态材料，这将告知未来的设计功能结构和治疗设备。具体地，设想了其形成和稳定性由连续消耗的燃料源的存在决定的材料，其中材料的寿命可通过改变所施加的燃料的剂量或改变材料所暴露的环境条件来调节。类似地，为了利用光作为燃料，设想了将所施加的光转换成驱动具有可调寿命的瞬态材料形成的定向线索的其他材料。通过化学燃料或使用光来模拟软材料中的瞬态，为软材料的设计指明了一个新的方向，该软材料具有植根于其自然模拟瞬态的增强功能，并用于推进许多材料应用。在这个融合的研究计划集成是一个持续的努力，建立和扩大实验室和课堂培训的分子工程领域，并通过研究，指导，社区推广，和经验培训的研究生学员在化学和材料科学。技术总结自然实现显着的功能，从材料存在于耗散非-平衡态;我们只需要观察细胞的结构和运动性就可以了，这种运动性是由肌动蛋白细胞骨架的ATP-燃料非平衡装配引起的。因此，该CAREER奖将研究和培训相结合，以创造具有燃料依赖性和瞬态稳定性的生物启发材料，并在燃料有限时消散。近年来，用合成的类似物重建自然材料的耗散非平衡态吸引了许多人。虽然努力几乎完全集中在燃料依赖的小分子组装，一个新的范例是在这里描述的燃料依赖的非平衡形成的主客体超分子水凝胶。该结果将通过依赖于可消耗化学燃料源的连续供应的识别基序，或通过使用光响应基序将光刺激致动成基序的改变的亲和力和/或动力学来实现。当特定的化学或轻燃料源有限时，这些材料将暂时存在并消散到其溶胶或弱凝胶的设计平衡状态。更广泛地说，主客体超分子识别提供了一类有用的软材料，其具有直接归因于其交联相互作用的动态性质的性质。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兴性质，并且还提供了许多工业应用所期望的特征。进一步整合这类材料的瞬时和燃料依赖性形成的能力寻求增加的仿生功能，以进一步扩展其可能的用途。该研究计划被放置在一个多学科的培训环境中，该环境旨在培养分子工程融合学科的领导者，并通过课堂教学进一步增强。此外，旨在改善化学和材料科学领域科学传播的培训旨在提高公众参与度，传达科学研究的重要性。该奖项反映了NSF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.