Understanding transport of nanoparticles in crowded, confined media through experiments and simulations

合成纳米颗粒可以用作载体，帮助将药物输送到体内的特定位置。 其他纳米颗粒似乎是工业生产的副产品，被释放到通过环境土壤移动的水源中。控制纳米颗粒在体内和环境中的运输和分布对于开发有效的治疗方法和减轻污染物影响的策略至关重要。该项目将支持研究纳米粒子在复杂环境中的运输，例如遇到这些生物和环境设置，其中纳米粒子运动受到附近限制表面和大分子（如聚合物）的影响。该研究将集中在流动驱动的纳米颗粒通过限制在多孔介质中的聚合物溶液的运输。实验将被用来图像颗粒，因为他们通过有限的聚合物流体移动。 互补的计算机模拟将有助于表征纳米颗粒传输机制以及纳米颗粒与周围流体中聚合物介导的附近表面之间的相互作用。研究结果将导致复杂流体中受限纳米颗粒运输的预测得到改进，这将有利于从药物输送到废水处理的应用。该研究小组将参加K-12学生和公众参与科学和工程的活动，包括在休斯顿儿童博物馆，休斯顿能源节和GRADE夏令营的妇女和学生的动手活动。研究人员将在德克萨斯州软物质会议上向当地的工业科学家和工程师传播该项目的结果。科学成果将通过可公开获取的开源软件项目和在线视频提供。该项目将采用粒子成像实验和计算模型来研究纳米粒子通过受限于多孔介质中的复杂流体的流动驱动传输。这一总体目标将通过将颗粒合成、成像和微加工技术与先进的模拟方法相结合来实现，以（1）阐明聚合物影响纳米颗粒通过受控多孔介质传输的机制，以及（2）了解这些机制如何受到颗粒形状和大小的影响。粒子成像和跟踪技术将用于表征纳米粒子通过多孔介质的传输，包括准二维纳米柱阵列和三维填充床。补充耗散粒子动力学模拟将被用来表征的结构和动力学的聚合物限制在多孔介质和聚合物介导的纳米粒子和附近的表面之间的耗尽相互作用。 纳米颗粒通过模型多孔介质的扩散和分散系数将在实验和模拟中测量为聚合物浓度和分子量以及颗粒尺寸和形状的函数。通过明智地结合模拟和实验，该项目将阐明控制纳米颗粒通过受限复杂流体的平衡和非平衡（流动驱动）传输的物理过程。结果将导致现有理论的修改，以解释影响纳米粒子在强约束中的传输和分散的聚合物介导过程。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。

Synthetic nanoparticles can be used as carriers to help deliver drugs to specific locations within the body. Other nanoparticles appear as byproducts from industrial manufacturing that are released into water sources that move through environmental soils. Controlling the transport and distribution of nanoparticles inside the body and in the environment is critical to developing effective therapeutic treatments and strategies for mitigating impacts of pollutants. This project will support research into the transport of nanoparticles in complex environments, such as those encountered these biological and environmental settings, where nanoparticle motions are influenced by the presence of nearby confining surfaces and large macromolecules such as polymers. The research will focus on the flow-driven transport of nanoparticles through solutions of polymers confined in porous media. Experiments will be used to image particles as they move through the confined polymeric fluids. Complementary computer simulations will help characterize mechanisms of nanoparticle transport and interactions between nanoparticles and nearby surfaces that are mediated by polymers in the surrounding fluid. Results of the research will lead to improved predictions of confined nanoparticle transport in complex fluids, which will benefit applications ranging from drug delivery to wastewater treatment. The research team will participate in activities that engage K-12 students and the general public in science and engineering, including hands-on activities at the Children’s Museum of Houston, the Houston Energy Festival, and the GRADE summer camp for women and students from underrepresented groups. The researchers will disseminate results of the project to local industrial scientists and engineers at the Texas Soft Matter Meeting. Scientific results will be available through publicly accessible open-source software projects and through online videos. This project will employ particle-imaging experiments and computational models to investigate the flow-driven transport of nanoparticles through complex fluids confined in porous media. This overarching objective will be achieved by integrating particle synthesis and imaging and microfabrication techniques with advanced simulation methods to (1) elucidate the mechanisms by which polymers influence the transport of nanoparticles through well-controlled porous media and (2) understand how these mechanisms are affected by particle shape and size. Particle imaging and tracking techniques will be used to characterize the transport of nanoparticles through porous media, including quasi-two-dimensional arrays of nanoposts and three-dimensional packed beds. Complementary dissipative particle dynamics simulations will be used to characterize the structure and dynamics of polymers confined in the porous media and the polymer-mediated depletion interactions between the nanoparticles and nearby surfaces. Diffusion and dispersion coefficients of nanoparticles through the model porous media will be measured in experiments and simulations as a function of polymer concentration and molecular weight and particle size and shape. By judiciously combining simulation and experiment, this project will elucidate the physical processes controlling the equilibrium and non-equilibrium (flow-driven) transport of nanoparticles through confined complex fluids. Results will lead to modifications of existing theories to account for polymer-mediated processes that affect nanoparticle transport and dispersion in strong confinement.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.