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Supplemental Material, sj-pdf-1-ijt-10.1177_10915818221093605 for Evaluation of Pulmonary Effects of 3-D Printer Emissions From Acrylonitrile Butadiene Styrene Using an Air-Liquid Interface Model of Primary Normal Human-Derived Bronchial Epithelial Cells by Mariana T. Farcas, Walter McKinney, Jayme Coyle, Marlene Orandle, W. Kyle Mandler, Aleksandr B. Stefaniak, Lauren Bowers, Lori Battelli, Diana Richardson, Mary A. Hammer, Sherri A. Friend, Samantha Service, Michael Kashon, Chaolong Qi, Duane R. Hammond, Treye A. Thomas, Joanna Matheson and Yong Qian in International Journal of Toxicology

Additional file 1.

Objective: Fused filament fabrication “3-dimensional (3-D)” printing has expanded beyond the workplace to 3-D printers and pens for use by children as toys to create objects. Materials and methods: Emissions from two brands of toy 3-D pens and one brand of toy 3-D printer were characterized in a 0.6 m3 chamber (particle number, size, elemental composition; concentrations of individual and total volatile organic compounds (TVOC)). The effects of print parameters on these emission metrics were evaluated using mixed-effects models. Emissions data were used to model particle lung deposition and TVOC exposure potential. Results: Geometric mean particle yields (106–1010 particles/g printed) and sizes (30–300 nm) and TVOC yields (3 in a classroom and 3–154 µg/m3 in a residential living room. Discussion: Potential exists for inhalation of organic vapors and metal-containing particles during use of these toys. Conclusions: If deemed appropriate, e.g. where multiple toys are used in a poorly ventilated area or a toy is positioned near a child’s breathing zone, control technologies should be implemented to reduce emissions and exposure risk.

Carboxylation of multi-walled carbon nanotubes is hypothesized to reduce the toxicity of these nanomaterials; however, literature reports are conflicting and the degree of carboxylic acid functionalization in different studies is not well quantified. The extent of carboxylation of multi-walled carbon nanotubes after acid treatment is quantified using affinity capillary electrophoresis. A polytryptophan peptide that contains a single arginine residue (WRWWWW) serves as a ligand in affinity capillary electrophoresis to assess the degree of carboxylation. The formation of peptide-nanotube ligand-receptor complex allows for the detection of the complex with a common UV absorbance detector based on light scatter rather than molecular absorbance. Dissociation constants (K(D)) are obtained by observing the migration shift of the WRWWWW peptide in background electrolyte at increasing concentrations of multi-walled carbon nanotubes. The K(D) values obtained from triplicate analyses of a single preparation of commercially available carboxylated multi-walled carbon nanotubes had a precision of 20% RSD (1.2 ± 0.2 mg/L). Preparations of multi-walled carbon nanotube remade from powdered samples (n = 3) generated K(D) values with 20% RSD (1.1 ± 0.2 mg/L) as well. When applied to commercially available multi-walled carbon nanotubes with different degrees of carboxylation, the capillary electrophoresis method yielded K(D) values that reflected higher levels of carboxylation. Zeta potential measurements of these preparations were not significantly different. The utility of the capillary electrophoresis method for evaluating acid treatment protocols was demonstrated by comparing K(D) values obtained for multi-walled carbon nanotubes subject to six different acidification times. While K(D) values were significantly different for acidification times ranging from 15 minutes to 3 hours, none of the zeta potential measurements of these samples were significantly different. This work is significant to research involving carbon nanotube toxicity because it provides a new metric to rapidly characterize carbon nanotubes obtained from different vendors, synthesized in laboratories using different procedures, or subject to different acidification protocols. Affinity capillary electrophoresis is a cost-effective, rapid and simple alternative to current technologies used to distinguish the degree of carbon nanotube carboxylation.

List of total proteins analyzed by RodentMAPÂŽ analyses, abbreviations, and alternate nomenclature. (PDF 32 kb)

Differentially expressed genes in lung tissue following exposure to 40Â Îźg of Gr20, Gr5, or Gr1. (PDF 38 kb)

List of total proteins analyzed by RodentMAPÂŽ analyses, abbreviations, and alternate nomenclature. (PDF 32 kb)

Differentially expressed genes in lung tissue following exposure to 40Â Îźg of Gr20, Gr5, or Gr1. (PDF 38 kb)

Genes contained in the pre-designed TaqManÂŽ array. (PDF 22 kb)

Genes contained in the pre-designed TaqManÂŽ array. (PDF 22 kb)

Healthcare workers have an elevated prevalence of asthma and related symptoms associated with the use of cleaning/disinfecting products. The objective of this study was to identify and characterize cleaning/disinfecting tasks and products used among hospital occupations.Workers from 14 occupations at five hospitals were monitored for 216 shifts, and work tasks and products used were recorded at five-minute intervals. The major chemical constituents of each product were identified from safety data sheets.Cleaning and disinfecting tasks were performed with a high frequency at least once per shift in many occupations. Medical equipment preparers, housekeepers, floor strippers/waxers, and endoscopy technicians spent on average 108-177 min/shift performing cleaning/disinfecting tasks. Many occupations used products containing amines and quaternary ammonium compounds for100 min/shift.This analysis demonstrates that many occupations besides housekeeping incur exposures to cleaning/disinfecting products, albeit for different durations and using products containing different chemicals.

Accurate characterization of the physicochemical properties of aerosols generated for inhalation toxicology studies is essential for obtaining meaningful results. Great emphasis must also be placed on characterizing particle properties of materials as administered in inhalation studies. Thus, research is needed to identify a suite of techniques capable of characterizing the multiple particle properties (i.e., size, mass, surface area, number) of a material that may influence toxicity. The purpose of this study was to characterize the morphology and investigate the size distribution of a model toxicant, beryllium. Beryllium metal, oxides, and alloy particles were aerodynamically size-separated using an aerosol cyclone, imaged dry using scanning electron microscopy (SEM), then characterized using phase contrast microscopy (PCM), a liquid suspension particle counter (LPC), and computer-controlled SEM (CCSEM). Beryllium metal powder was compact with smaller sub-micrometer size particles attached to the surface of larger particles, whereas the beryllium oxides and alloy particles were clusters of primary particles. As expected, the geometric mean (GM) diameter of metal powder determined using PCM decreased with aerodynamic size, but when suspended in liquid for LPC or CCSEM analysis, the GM diameter decreased by a factor of two (p < 0.001). This observation suggested that the smaller submicrometer size particles attached to the surface of larger particles and/or particle agglomerates detach in liquid, thereby shifting the particle size distribution downward. The GM diameters of the oxide materials were similar regardless of sizing technique, but observed differences were generally significant (p < 0.001). For oxides, aerodynamic cluster size will dictate deposition in the lung, but primary particle size may influence biological activity. The GM diameter of alloy particles determined using PCM became smaller with decreasing aerodynamic size fraction; however, when suspended in liquid for CCSEM and LPC analyses, GM particle size decreased by a factor of two (p < 0.001) suggesting that alloy particles detach in liquid. Detachment of particles in liquid could have significance for the expected versus actual size (and number) distribution of aerosol delivered to an exposure subject. Thus, a suite of complimentary analytical techniques may be necessary for estimating size distribution. Consideration should be given to thoroughly understanding the influence of any liquid vehicle which may alter the expected aerosol size distribution.

Silver is increasingly being used in garments to exploit its antibacterial properties. Information on the presence of silver nanoparticles (AgNPs) in garments and their in vivo penetration across healthy and impaired skin from use is limited. We investigated the presence of AgNPs in a silver containing garment and in the stratum corneum (SC) of healthy subjects (CTRLs) and individuals with atopic dermatitis (AD). Seven CTRLs and seven AD patients wore a silver sleeve (13% Ag w/w) 8 h/day for five days on a forearm and a placebo sleeve on the other forearm. After five days, the layers of the SC were collected by adhesive tapes. The silver particles in the garment and SC were characterized by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX) and atomic force microscopy (AFM). AFM and SEM revealed the presence of sub-micrometre particles having a broad range of sizes (30–500 nm) on the surface of the garment that were identified as silver. On the SC tapes collected from different depths, aggregates with a wide range of sizes (150 nm–2 μm) and morphologies were found. Most aggregates contained primarily silver, although some also contained chlorine and sulfur. There was no clear difference in the number or size of the aggregates observed in SC between healthy and AD subjects. After use, AgNPs and their aggregates were present in the SC at different depths of both healthy subjects and AD patients. Their micrometre size suggests that aggregation likely occurred in the SC.