Evaluation of Enhanced Darkfield Microscopy and Hyperspectral Imaging for Rapid Screening of TiO2 and SiO2 Nanoscale Particles Captured on Filter Media

Details

• Personal Author:
  Brenner SA ; Dozier, Alan K. ; Eastlake AC ; Neu-Baker NM
• Description:
  Here we report on initial efforts to evaluate enhanced darkfield microscopy (EDFM) and light scattering Vis-NIR hyperspectral imaging (HSI) as a rapid screening tool for the offline analysis of mixed cellulose ester (MCE) filter media used to collect airborne nanoparticulate from work environments. For this study, the materials of interest were nanoscale titanium dioxide (TiO2) and silicon dioxide (SiO2; silica), chosen for their frequent use in consumer products. TiO2 and SiO2 nanoscale particles (NPs) were collected on MCE filter media and were imaged and analyzed via EDFM-HSI. When visualized by EDFM, TiO2 and SiO2 NPs were readily apparent as bright spherical structures against a dark background. Moreover, TiO2 and SiO2 NPs were identified in hyperspectral images. EDFM-HSI images and data were compared to scanning transmission electron microscopy (STEM), a NIST-traceable technique for particle size analysis, and the current gold standard for offline analysis of filter media. As expected, STEM provided more accurate sizing and morphology data when compared to EDFM-HSI, but is not ideal for rapid screening of the presence of NPs of interest since it is a costly, low-throughput technique. In this study, we demonstrate the utility of EDFM-HSI in rapidly visualizing and identifying TiO2 and SiO2 NPs on MCE filters. This screening method may prove useful in expediting time-to-knowledge compared to electron microscopy. Future work will expand this evaluation to other industrially relevant NPs, other filter media types, and real-world filter samples from occupational exposure assessments. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Occupational Health Safety Silicon Dioxide Titanium
• Keywords:
  Airborne Particles Author Keywords: Mixed Cellulose Ester Exposure Assessment Filters Imaging Techniques Nanoparticles Nanotechnology Occupational Exposure Assessment Pixel Classification Reference Spectral Library Scanning Electron Microscopy Silicon Dioxide Spectral Angle Mapper Titanium Dioxide Visual Images

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• ISSN:
  1059-910X
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Journal Article
• Place as Subject:
  Maryland ; New York ; Ohio ; OSHA Region 2 ; OSHA Region 3 ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; DSI - Division of Science Integration
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  84
• Issue:
  12
• NIOSHTIC Number:
  nn:20063090
• Citation:
  Microsc Res Tech 2021 Dec; 84(12):2968-2976
• Contact Point Address:
  Nicole M. Neu-Baker, College of Nanoscale Science, Nanobioscience Constellation, State University of New York (SUNY) Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
• Email:
  nneu@sunypoly.edu
• CAS Registry Number:
  Silica (CAS RN 7631-86-9) ; Titania (CAS RN 13463-67-7)
• Federal Fiscal Year:
  2022
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  True
• Source Full Name:
  Microscopy Research and Technique
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6bd3b9810161b9378d1a6768c7f3cb2df6856941e9c6404515876500cf399d0118a44b7fad5a5220ae39df1696327c6954be73bad5deb646ff4a72504bf9d02a
• Download URL:
  https://stacks.cdc.gov/view/cdc/226214/cdc_226214_DS1.pdf
• File Type:
  [PDF - 3.00 MB ]