Printer Emitted Particles: Are they safe?

Engineered nanomaterials (ENMs) incorporated into toner formulations of toner used in every day laser printers. During the print jobs it is likely that the particles can be released in the air.

Recently, our group developed a lab based Printer Exposure Generation System that allows the generation and sampling of airborne PEPs for subsequent physicochemical, morphological and toxicological analyses. This platform was used to evaluate PM emission profiles from 11 laser printers currently on the market. It was shown that the particle number concentration of PEPs varied across different printer models/manufacturers and reached as high as 1.3 million particles/cm3 and with modal diameters <200 nm. The detailed assessment of both toners and PEPs confirmed not only the presence of nanoscale materials in the airborne state but also their complex chemistries, which include elemental and organic carbon and inorganic compounds such as metals and metal oxides. It has been now confirmed that toners are classified as nano-enabled products. Additionally, we have performed in-depth toxicological analysis evaluating the effects of exposure to PEPs using physiologically relevant cell lines in both mono- and co-culture experimental systems. We have shown that PEPs caused significant cytotoxicity, membrane integrity damage, reactive oxygen species (ROS) production, pro-inflammatory cytokine release, angiogenesis, actin remodeling, gap cell junctions and epigenetic changes in cells at doses comparable to those from real world exposure scenarios representative of inhalation exposures in the range of 1-200 hours. We may conclude that laser printer-emitted engineered nanoparticles can be deleterious to lung cells and may cause persistent genetic modifications that could translate to pulmonary disorders.


  1. Pirela SV, Pyrgiotakis G, Bello D, Thomas T, Castranova V, Demokritou P. 2014a. Development and characterization of an exposure platform suitable for physico-chemical, morphological and toxicological characterization of printer-emitted particles (peps). Inhal Toxicol 26:400-408.
  2. Pirela SV, Sotiriou GA, Bello D, Shafer M, Bunker KL, Castranova V, et al. 2014b. Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products. Nanotoxicology:1-9.
  3. Pirela SV, Miousse IR, Lu X, Castranova V, Thomas T, Qian Y, et al. 2015. Laser printer-emitted engineered nanoparticles lead to cytotoxicity, inflammation and changes in dna methylation in human cells. Environmental health perspectives.
  4. Sisler JD, Pirela SV, Friend S, Farcas M, Schwegler-Berry D, Shvedova A, et al. 2014. Small airway epithelial cells exposure to printer-emitted engineered nanoparticles induces cellular effects on human microvascular endothelial cells in an alveolar-capillary co-culture model. Nanotoxicology:1-11.