Fiber sampling technique and counting protocol development for carbon nanotubes

碳纳米管纤维采样技术和计数协议开发

• 批准号: 10593857
• 负责人: Candace SuJung Tsai
• 金额: $ 19.26万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10593857
• 关键词: Fiber; sampling; technique; counting; protocol

PROJECT ABSTRACT The goal of this project is to develop a new method for fiber sampling. The method currently used for airborne sampling of carbon nanotubes (CNTs) is adapted from micrometer-scale asbestos sampling. To achieve our goal, we will study surface properties of different CNTs and sampling filters contributing to efficiency, develop a novel image analysis protocol with our algorithms, use a newly developed nanoparticle (NP) isokinetic diffusion sampler, simulate and elucidate the particle behavior, and produce a new method suitable to CNTs sampling. Burden: Exposure to airborne CNTs has been of highest concern following their designation as a potential human carcinogen. The potential health effects of CNTs have shown some similarity to those of asbestos fibers in animal models. CNTs global market is projected to reach $103.2 billion by 2030 with 16.3% annual growth. The fiber sampling method used for asbestos has been a recommended method for sampling CNT fibers. CNTs contain individual fibers with diameters that are one tenth to one hundredth that of asbestos fibers. The NIOSH Methods 7402 was found to be very challenging and time consuming for identifying a few very fine CNT fibers on a grid sample under electron microscopy. Questions raised by this challenge include whether the number and size of CNT fibers collected by 7402 method are representative of those in the air, whether these sizes are affected by the sampling and extensive processing required by the method, and how the exposure to fine fibers can be quantified properly to evaluate associated health effects when this method is not yet validated for CNT. Need: A new method and technique for sampling fine fibers to 1) collect fibers efficiently in the sampled air without loss, 2) directly analyze the collected fibers with minimal processing of the sample, and 3) easily count the fibers to obtain the concentration and size, which will resolve the lack of accuracy of exposure measurements and the significant time requirement of sample analysis. When used for CNTs, the collection efficiency and performance of sampling and analysis must be evaluated. It is critical to design a new sampling substrate because the currently used mixed cellulose ester (MCE) filter for collecting asbestos may not be suitable for collecting CNTs. The fibers collected on the MCE filter need to be processed for transfer to a grid for analysis, small fibers can be agglomerated or lost. A new sampling method and substrate that can effectively collect fibers to be analyzed directly will prevent the loss or change of collected fibers through the transfer process. Impact: The wide range of applications that use fiber materials such as CNTs, asbestos and fiberglass and other NPs can employ the developed protocol and method to effectively quantify the exposure level in terms of fiber/particle concentration. This information may change the current measurement metric for CNTs from mass concentration to fiber/particle number concentration. Using more precise counting can characterize the exposure concentration at a very low and difficult to measure mass concentration and provide associations to related health effects for a measurement below the current limit of mass quantification for CNTs.

项目摘要 该项目的目的是开发一种用于纤维采样的新方法。当前用于机载的方法 碳纳米管（CNT）的采样是根据千分尺尺度的石棉采样的。实现我们的 目标，我们将研究不同CNT和采样过滤器的表面特性，有助于效率，发展 使用我们的算法的新型图像分析方案，使用新开发的纳米颗粒（NP）同动扩散 采样器，模拟和阐明粒子行为，并产生一种适合CNTS采样的新方法。 负担：空气中CNT的暴露在其称为潜力后一直是最大的关注点 人致癌。 CNT的潜在健康影响与石棉纤维的健康相似 在动物模型中。 CNTS全球市场预计到2030年将达到1002亿美元，年增长率为16.3％。 石棉使用的纤维采样方法已成为对CNT纤维进行采样的推荐方法。 CNT 包含单个纤维，其直径为十分之一，即石棉纤维的纤维。 Niosh 方法7402被发现非常具有挑战性且耗时，以识别一些非常细的CNT纤维 在电子显微镜下的网格样品上。这项挑战提出的问题包括数字和数字是否 7402方法收集的CNT纤维的尺寸代表了空中的大小，这些尺寸是否为 受该方法所需的采样和广泛处理的影响，以及如何暴露于细纤维 当尚未针对CNT验证此方法时，可以正确量化以评估相关的健康效果。 需求：一种新方法和技术，用于对细纤维进行采样1）在采样的空气中有效收集纤维 不损失，2）直接通过样品的最小加工来直接分析收集的纤维，3）轻松计数 获得浓度和大小的纤维，这将解决缺乏暴露测量的准确性 以及样本分析的显着时间要求。当用于CNT时，收集效率和 必须评估采样和分析的性能。设计新的采样基板至关重要 因为当前使用的混合纤维素酯（MCE）过滤器用于收集石棉可能不适合 收集CNT。需要处理在MCE滤波器上收集的纤维以传输到网格以进行分析， 小纤维可能会被结合或丢失。一种可以有效收集纤维的新采样方法和底物 直接分析将防止通过转移过程损失或变化。 影响：使用CNT，石棉和玻璃纤维等纤维材料的广泛应用 NP可以采用开发的协议和方法来有效地量化 纤维/颗粒浓度。此信息可能会改变质量中CNT的当前测量指标 浓度到纤维/颗粒数浓度。使用更精确的计数可以表征曝光 浓度非常低，难以测量质量浓度，并为相关的关联 测量的健康效应低于当前CNT质量定量的极限。