"Nanostructured Injectable Hydrogels with Tunable ""Smart"" Properties"

水凝胶，水膨胀聚合物网络，在解决当前环境（例如土壤修复，农药输送），消费品（例如保湿剂，洗发水），食品（例如风味掩蔽，营养补充剂，安全包装）和药物（药物的控制输送，医疗粘合剂或细胞生长支持）方面具有巨大的潜力。鉴于水凝胶的化学、物理和机械性能可以设计成模拟生物软组织（如肌肉），使水凝胶能够满足其他类型材料无法满足的应用需求，生物应用已经引起了特别的兴趣。为了在这些应用中有效地应用水凝胶，必须精确控制水凝胶的纳米尺度和表面性质，以达到所需的药物释放速度、细胞相互作用或粘附强度。拟议的研究旨在开发可注射的水凝胶，基于微凝胶（即小水凝胶颗粒）和/或工程聚合物，这些聚合物在注入低粘度前体后迅速形成水凝胶，在纳米尺度上具有良好控制的化学和物理性质。我们的方法是开发一系列具有明确性质的化学反应构建块，然后将它们以不同的组合和不同的比例混合；通过控制同时发生的化学反应来形成凝胶，以及在所选择的构建块之间的物理相互作用，有望创造出定向的水凝胶和微凝胶结构，并以设定的速率降解。将“智能”材料结合到构建块中，其特性在某些刺激（例如温度、光或pH值）下发生变化，从而进一步提供了对凝胶特性的外部控制。这种材料在设计改进的传感器、延长药物治疗的持续时间（提高疗效同时减少药物治疗的频率）、控制细胞粘附（改善伤口愈合）、在组织之间建立牢固、灵活的纽带（改善湿粘合剂）以及为纳米技术创造快速反应的“门”方面具有巨大的潜力。拟议的研究计划还为跨学科培训创造了机会，以解决当前的技术挑战。

Hydrogels, water-swollen polymer networks, have tremendous potential for addressing current challenges in the environment (e.g. soil remediation, pesticide delivery), consumer products (e.g. moisturizers, shampoos), food (e.g. flavour masking, nutritional supplements, safe packaging), and medicine (controlled delivery of drugs, medical adhesives, or cell growth supports). Biological applications have attracted particular interest given that the chemical, physical, and mechanical properties of hydrogels can be designed to mimic biological soft tissues such as muscle, enabling hydrogels to satisfy application needs that other types of materials cannot. To effectively apply hydrogels in these applications, the nano-scale and surface properties of hydrogels must be precisely controlled to achieve the drug release rate, cell interaction, or adhesion strength required. The proposed research aims to develop injectable hydrogels, based on microgels (i.e. small hydrogel particles) and/or engineered polymers that rapidly form hydrogels upon injection from low-viscosity precursors, that have well-controlled chemistries and physical properties on the nano-scale. Our approach is to develop a range of chemically-reactive building blocks with well-defined properties and then mix them in different combinations and different ratios; manipulation of the simultaneous chemical reaction to form a gel and physical interactions between the building blocks selected is anticipated to create oriented hydrogel and microgel structures that degrade at programmed rates. The incorporation of "smart" materials into the building blocks whose properties change upon some stimulus (e.g. temperature, light, or pH) provides further, external control over the gel properties. Such materials have significant potential for designing improved sensors, enabling prolonged duration drug therapies (improving the efficacy while reducing the frequency of drug treatments), controlling cell adhesion (improving wound healing), creating strong, flexible bonds between tissues (improving wet adhesives), and creating fast-responding "gates" for nanotechnology. The proposed research program also creates opportunities for interdisciplinary training integral to address current technology challenges.