S.V. Pirela, D. Bello, V. Castranova, Y. Qian, P. Demokritou
T.H. Chan School of Public Health, Harvard University,
Keywords: laser printers, laser printer-emitted particles, nanoparticles, life-cycle exposure
Summary:Engineered Nanoparticles Emitted From Laser Printers: Environmental Health Implications Sandra V. Pirela1, Dhimiter Bello1,2, Vincent Castranova3, Yong Qian4, Philip Demokritou1 1 Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts 2 University of Massachusetts, Lowell, Massachusetts 3 Department of Pharmaceutical Sciences/Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia 4 Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia The use of laser printers has been associated with emission of particulate matter (PM), ozone and VOCs. Recently, there have been concerns due to incorporation of engineered nanomaterials (ENMs) into toner formulations for quality improvements; however, the implications of releases of ENMs during consumer use on environmental health are unknown. Thus, a multi-tiered methodology was designed to physico-chemically, morphologically and toxicologically characterize the engineered nanomaterials (ENMs) released from nano-enabled toners during printing. A printer exposure generation system (PEGS) suitable for the physico-chemical and toxicological assessment of PEPs was developed and used to screen commercially available laser printers. The exposure platform consists of a glovebox type environmental chamber for uninterrupted printer operation, real-time and time-integrated particle sampling instrumentation for size fractionation and sampling of PEPs and an exposure chamber for inhalation toxicological studies. Results from our extensive analysis show laser printer peak emissions are brand-independent and varied between 3,000 to 1,300,000 particles/cm3 with modal diameters ranging from 49 to 208 nm. Moreover, it was confirmed that the toner formulation contained materials of complex chemical composition, primarily of organic nature, and more importantly includes nanoscale materials such as metal and metal oxides (e.g., Cu, Mn Al, Fe, Mn, Si). More importantly, it was illustrated that during printing, ENMs from the toners make their way into the air, resulting to significant PM exposures. In order to assess the potential toxicity of PEPs, the biological responses to exposure to PM emitted by a high-emitting laser printer were evaluated using cellular and animal experimental models. Both models showed PEPs are biologically reactive and may cause significant cytotoxicity, membrane integrity damage, reactive oxygen species production, pro-inflammatory cytokine release, angiogenesis, cytoskeletal and epigenetic changes as well as overall lung inflammation. Additionally, adverse effects on the cardiopulmonary system and genomic stability following exposure to PEPs (PM0.1) are currently being evaluated using a rodent experimental model. Overall, our work highlights the importance of understanding life-cycle nano-environmental health and safety implications of nano-enabled products and assessing real world exposures, as well as the associated toxicological properties of the emitted PM rather than focusing on ‘‘raw’’ toner powder used by laser printers. These results suggest that laser printer-emitted particles are chemically complex and bioactive and thus, may be deleterious to the physiology of individuals exposed to these particles both in a residential and occupational setting.