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

Zia, Roseanna n .提案号：1351184本CAREER提案的目标是通过发现和阐明胶体凝胶突然崩溃的潜在机制来发展凝胶稳定性的预测理论。这一研究对于合理设计可注射给药平台、可移植组织支架等软性生物材料，以帮助身体无法产生此类组织的患者。这种理论的发展具有潜在的变革性，因为它将建立对凝胶崩溃的定性理解。注射凝胶由于其生物相容性、对不同治疗成分的可调节性和微创性，在过去十年中成为组织工程和药物输送的首要工具。然而，这种凝胶容易突然失效。脚手架毫无征兆地坍塌成致密的、没有结构的沉积物。在这种情况下，活性化合物的运输急剧减少，支架状的结构支撑也就丧失了。由于难以对凝胶崩塌进行详细的观察、模拟大尺度凝胶演化的计算费用以及阻滞胶体动力学理论的限制，目前还无法预测凝胶的崩塌。这项研究将创造一个窗口，通过它来观察粒子和网络重新排列的精确细节，实时崩溃，因为它发生了。这将产生一个相位图，第一次预测坍缩和特征长度尺度、年龄、吸引力和导致坍缩的潜在力量。

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.