Engineered Nanoparticle Release from Personal Protective Clothing: Implications for Inhalation Exposure

Abstract

In this study, we investigated engineered nanoparticle (ENP) release associated with the contamination of personal protective clothing during the simulated motion of the human wearing the ENP-contaminated protective clothing and evaluated the relative ENP retention on the fabric. The release of airborne ENPs can contribute to inhalation exposure, which is the route of exposure of most concern to cause adverse health effects in the pulmonary system. The evaluation focuses on four popular fabric materials making the laboratory coats (cotton, polypropylene, polyester cotton blend, and Tyvek) and three types of ENPs (Al2O3, carbon black (CB), and carbon nanotube (CNT)). The magnitudes of particle contamination and resuspension were investigated by measuring the number concentration increase of airborne particles in sizes of 10 nm to 10 μm and the weight changes on fabric pieces. Collected aerosol particles and contaminated fabric surfaces were further characterized for understanding particle morphology, elements, agglomeration, and surface contamination status. The particle resuspension from the contaminated lab coat fabric was found to vary by the type of fabric material. Cotton fabric showed the highest level of particle resuspension for all three tested ENPs. Data were evaluated to determine the dominant forces responsible for ENP adhesion on the surface of the fabric. Tyvek fabric was determined as the best fabric for trapping Al2O3 and carbon black ENPs, indicating less resuspension of particles, meaning lower subsequent release, but not durable enough to wear for the long term compared with other fabrics.

Effects of Surface Hydrophobicity of Lab Coat Fabrics on Nanoparticle Attachment and Resuspension: Implications for Fabrics Used for Making Protective Clothing or Work Uniform

“…Although those samples were 0.060 in. (compared to the ∼0.010 in ref used in this work) and treated under harsher plasma parameters, SEM images of the treated PP did not appear to have the same scale of increased surface roughness when compared to the treated high-density polyethylene. The previously published results also had similar trends to the data presented herein when comparing WCA measurements of PP and high-density polyethylene.…”

“…There are two forces that can contribute to ENP interactions with fabrics, which we will briefly discuss here. One contributing factor is Hamaker attraction or van der Waals forces between a particle and a substrate . Because of the large relative size difference of the ENPs from the fabric threads, this intermolecular force can be approximated using the individual Hamaker constants of the ENPs and the fabric interacting with themselves.…”

“…One contributing factor is Hamaker attraction or van der Waals forces between a particle and a substrate. 26 Because of the large relative size difference of the ENPs from the fabric threads, this intermolecular force can be approximated using the individual Hamaker constants of the ENPs and the fabric interacting with themselves. This calculation, however, is complicated to perform as finding reliable Hamaker constants for uncommon or modified materials (i.e., the ENP and plasma treated fabrics) is difficult, and "equivalent" material substitutions will need to be used.…”

“…Based on the safety protocol for CNTs, fabrics were contaminated with CNTs in an enclosed hood in a class 100 cleanroom and using a Powder Dispersion Generator RBG 1000 (operated at p = 2 bar and 10 mm/h feeding rate for 10 min) to limit CNT agglomeration. 26 After patch contamination, the air was purged/cleaned inside the enclosure. Two of the four contaminated patches were each shaken manually for 2 min to release the ENPs from the fabrics (these samples are referred to as "shaken" or "after shaking").…”

“…Experiments were performed using a Kruss DSA30 goniometer under ambient laboratory conditions (22 ± 2 °C and <25% relative humidity) to measure the wettability of the uncontaminated fabrics, as described previously. 26 Briefly, static water contact angle (WCA) measurements were collected with a 2 μL drop of ultrapure H 2 O (Millipore, ≥18 MΩ) and absorption rates using a 4 μL drop. The absorption rate was calculated by dividing the drop volume by the time it took for the drop to be fully adsorbed by the material.…”