CAREER: Rheology, Stability, and Sudden Collapse of Colloidal Gels: A Micromechanical Study

Pi：Zia，Roseanna N.建议编号：1351184这项职业计划的目标是通过发现和阐明胶体凝胶突然崩溃的潜在机制，开发一种预测凝胶稳定性的理论。这类研究对于合理设计软性生物材料非常重要，例如可注射给药平台和可移植组织支架，用于那些身体无法产生此类组织的患者。这一理论的发展具有潜在的变革性，因为它将建立对凝胶崩塌的定性理解。在过去的十年中，可注射凝胶因其生物相容性、可调节到不同的治疗部分以及微创递送而成为组织工程和药物输送的主要工具。然而，这种凝胶很容易突然失效？在没有警告的情况下，脚手架坍塌成致密的、无结构的沉积物。在这种情况下，活性化合物的运输大大减少，支架状的结构支撑也就丢失了。目前还不可能预测凝胶的崩塌，因为崩塌的详细观察很困难，模拟大规模凝胶演化的计算费用很高，以及有限的胶体滞留动力学理论。这项研究将创建一个窗口，通过它来查看粒子和网络重新排列的精确细节，以及发生时的实时崩溃。这将产生一个相图，第一次预测崩塌和导致崩塌的特征长度比例、年龄、吸引力和潜在力量。

PI: Zia, Roseanna N.Proposal Number: 1351184The goal of this CAREER proposal is to develop a predictive theory for gel stability by discovering and elucidating the underlying mechanisms of the sudden collapse of colloidal gels. Such research is important for the rational design of soft biomaterials, such as injectable drug delivery platforms and transplantable tissue scaffolds to patients whose body cannot generate such tissue. The development of such theory is potentially transformative, because it would establish qualitative understanding of gel collapse.Injectable gels have emerged in the past decade as a premier tool in tissue engineering and drug delivery due to their biocompatibility, tunability to different therapeutic moieties, and minimally invasive delivery. However, such gels are susceptible to sudden failure ? without warning the scaffold collapses into a dense, structureless sediment. In that case, the transport of active compounds is dramatically curtailed, and the scaffold-like structural support is lost. It is not currently possible to predict gel collapse owing to the difficulty of detailed observation of collapse, the computational expense of simulating large-scale gel evolution, and limited theory of arrested colloidal dynamics. This study will create a window through which to view, in exacting detail of particle and network rearrangements, the real-time collapse, as it occurs. This will yield a phase map that, for the first time, predicts the collapse and the characteristic length scale, age, attraction and underlying forces that lead to collapse.