High Throughput Collection and Detection of Environmental Nanoparticles

该提案的目标是通过建立一种全新的技术来克服当前环境采样仪器的局限性，该技术将使纳米颗粒能够以非常高的流速收集和浓缩，从而可以使用连续流动的微流体方法结合粒度分析直接检测纳米颗粒。这种方法提供了一种独特的潜力，可以提供纳米颗粒暴露水平的更详细的图像，同时提供对突发环境变化的响应能力。首先，他们将利用他们最近发现的微流体界面荧光现象作为创新纳米颗粒检测方法的基础。包括灵敏度和特异性在内的基本参数将被表征，以建立与当前一代仪器比较的检测限。其次，他们将利用他们在气溶胶采样方面的广泛专业知识，建立一个实时自主湿壁旋风（WWC）收集器系统，该系统最适合于纳米材料的连续环境采样。从WWC的输出将被馈送到微流体检测组件，以提供自动在线检测能力。纳米颗粒捕获收集器的设计将以协同计算流体动力学模拟和高速、高分辨率颗粒图像测速测量为指导，以表征WWC内的三维流场。实验将集中在TiO2， Al2O3和SiO2纳米颗粒作为模型材料。智力优势：这项工作的主要成果将是设计一个原型纳米粒子探测器系统的基础工程知识，该系统优化了高通量环境采样。其他成果包括：(1)提高了对纳米颗粒负载悬浮液微流体中吸附界面络合效应的基本理解；(2)评估与微流体检测系统相关的灵敏度、选择性和检测限的数据；(3)一个新的工具来评估整个工作空间内环境纳米颗粒浓度的动态变化，再加上颗粒大小，以更好地评估潜在的毒性。更广泛的影响：这项工作的多学科性质将被用来开发新的研究经验和课程，使研究生和本科生都能接触到纳米技术的前沿领域。通过参与现有的NSF REU和SROP项目，将特别强调少数族裔的招聘。他们还计划开展一些推广活动，通过定期向高中学生和教师举办研讨会和开放实验室，提高社会对纳米粒子及其环境影响的认识。他们还将举办访问项目，并为工业和医疗合作者开放实验室。新颖性：与该领域以前的工作相比，他们提出的概念的新颖性是双重的。首先，它提供了一种采样环境纳米材料的方法，其通量足够高，可以进行连续分析。其次，它引入了一种全新的基于微流体的纳米颗粒检测方法，该方法需要相对简单的仪器，但在低浓度下也很敏感。这种检测方法的发展将通过提供有关吸收性染料-纳米颗粒相互作用及其在控制所产生的配合物的荧光增强/猝灭中的作用的新的基本见解来推进工程科学。更广泛地说，这项工作将能够评估整个工作空间内环境纳米颗粒浓度的动态变化，以及颗粒大小，以更好地评估潜在的毒性。当前一代仪器不具备的功能。

The goal of this proposal is to overcome the limitations of current environmental sampling instruments by establishing an entirely new technique that will enable nanoparticles to be collected and concentrated at very high flow rates, so that they can be directly detected using a continuous-flow microfluidic approach coupled with particle sizing analysis. This approach offers unique potential to deliver a more detailed picture of nanoparticle exposure levels while simultaneously providing the ability to respond to sudden environmental changes.First, they will harness microfluidic interfacial fluorescence phenomena they have recently discovered as the basis for an innovative nanoparticle detection approach. Fundamental parameters including sensitivity and specificity will be characterized to establish detection limits for comparison with current-generation instrumentation. Second, they will leverage their extensive expertise in aerosol sampling to build a real-time autonomous wetted wall cyclone (WWC) collector system optimally suited for continuous environmental sampling of nanomaterials. Output from the WWC will be fed into the microfluidic detection component to provide automated on-line detection capability. Collector design for nanoparticle capture will be guided by coordinated computational fluid dynamics simulations and high-speed, highresolution particle image velocimetry measurements to characterize the 3-D flow fields within the WWC.Experiments will focus on TiO2, Al2O3, and SiO2 nanoparticles as model materials.Intellectual Merit: The primary outcome of this work will be the fundamental engineering knowledge to design a prototype nanoparticle detector system optimized for high-throughput environmental sampling.Additional outcomes include (1) an improved fundamental understanding about adsorptive interfacial complexation effects in microfluidic flows of nanoparticle-laden suspensions; (2) data assessing the sensitivity, selectivity, and limits of detection associated with the microfluidic-based detection system; and (3) a new tool to assess dynamic changes in environmental nanoparticle concentrations within an entire workspace volume, coupled with particle sizing to better assess potential toxicity.Broader Impacts: The multidisciplinary nature of this work will be leveraged to develop new research experiences and courses that expose both graduate and undergraduate students to areas at the frontier of nanotechnology. Minority recruitment will be particularly emphasized through their involvement withexisting NSF REU and SROP programs. They also plan a number of outreach activities to increase societal awareness of nanoparticles and their environmental impact by hosting seminars and open lab access on a regular basis to high school students and teachers. They will also host visiting programs and open lab access for industrial and medical collaborators.Novelty: The novelty of their proposed concept compared to previous work in the field is twofold. First, it provides a method to sample environmental nanomaterials with throughput high enough to permit continuous analysis. Second, it introduces an entirely new microfluidic-based nanoparticle detectionapproach that requires relatively simple instrumentation yet is sensitive at low concentrations.Development of this detection method will advance engineering science by providing new fundamental insights about absorptive dye-nanoparticle interactions and their role in governing fluorescence enhancement/quenching of the resulting complexes. More broadly, this work will enable assessment ofdynamic changes in environmental nanoparticle concentrations within an entire workspace volume, coupled with particle sizing to better assess potential toxicity?capabilities not available in current generation instruments.