Landon T Holbrook1, Kirby L Zeman1, Alyssa Burke1, Ilona Jaspers1,2, William D Bennett1. 1. 1 Center for Environmental Medicine, Asthma, and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. 2. 2 School of Medicine, Department of Pediatrics and Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Abstract
BACKGROUND: Electronic cigarettes (ECIGs) are widely used, but their health effects are not well known. ECIG exposure is difficult to quantify, and a direct measurement of deposition would be beneficial to in vivo and in vitro toxicity studies. The aim of this study was to demonstrate effective radiolabeling of an ECIG. METHODS: A technetium-99m-labeled carbon ultrafine (TCU) aerosol was generated and introduced to a fourth-generation ECIG before nucleation and aerosol formation. The aerosolized e-liquid was a commercially available strawberry flavor containing 1.2% nicotine in a 55% propylene glycol and 45% vegetable glycerine base. An ECIG power setting of 100 W was selected. Mass and radioactivity were measured on each stage within a Sierra Cascade Impactor at 14 L/min to verify the labeling technique using the calculated aerodynamic diameters. A strong positive correlation (R2 > 0.95) between the percent activity and percent mass deposition on each stage provides a reliable validation of colocation. RESULTS: Unlabeled ECIG aerosol from the chosen e-liquid produced a mass median aerodynamic diameter (MMAD) of 0.85 μm. An ECIG labeled with TCU produced an aerosol with an activity median aerodynamic diameter of 0.84 μm and an MMAD of 0.84 μm. The relative mass versus radioactivity on each plate was highly correlated (average R2 = 0.973, p < 0.001). CONCLUSION: A TCU radiolabel was generated and shown to associate with the mass of an aerosol produced by a typical commercially available ECIG. Thus, the radioactivity of the deposited aerosol may be used to determine ECIG aerosol deposition for the future in vivo and in vitro dosimetry studies of the third- and fourth-generation ECIGs.
BACKGROUND: Electronic cigarettes (ECIGs) are widely used, but their health effects are not well known. ECIG exposure is difficult to quantify, and a direct measurement of deposition would be beneficial to in vivo and in vitro toxicity studies. The aim of this study was to demonstrate effective radiolabeling of an ECIG. METHODS: A technetium-99m-labeled carbon ultrafine (TCU) aerosol was generated and introduced to a fourth-generation ECIG before nucleation and aerosol formation. The aerosolized e-liquid was a commercially available strawberry flavor containing 1.2% nicotine in a 55% propylene glycol and 45% vegetable glycerine base. An ECIG power setting of 100 W was selected. Mass and radioactivity were measured on each stage within a Sierra Cascade Impactor at 14 L/min to verify the labeling technique using the calculated aerodynamic diameters. A strong positive correlation (R2 > 0.95) between the percent activity and percent mass deposition on each stage provides a reliable validation of colocation. RESULTS: Unlabeled ECIG aerosol from the chosen e-liquid produced a mass median aerodynamic diameter (MMAD) of 0.85 μm. An ECIG labeled with TCU produced an aerosol with an activity median aerodynamic diameter of 0.84 μm and an MMAD of 0.84 μm. The relative mass versus radioactivity on each plate was highly correlated (average R2 = 0.973, p < 0.001). CONCLUSION: A TCU radiolabel was generated and shown to associate with the mass of an aerosol produced by a typical commercially available ECIG. Thus, the radioactivity of the deposited aerosol may be used to determine ECIG aerosol deposition for the future in vivo and in vitro dosimetry studies of the third- and fourth-generation ECIGs.
Authors: Sunalene G Devadason; Hak-Kim Chan; Sabine Haeussermann; Claudius Kietzig; Philip J Kuehl; Stephen Newman; Knut Sommerer; Glyn Taylor Journal: J Aerosol Med Pulm Drug Deliv Date: 2012-12 Impact factor: 2.849
Authors: Günter Oberdörster; Zachary Sharp; Viorel Atudorei; Alison Elder; Robert Gelein; Alex Lunts; Wolfgang Kreyling; Christopher Cox Journal: J Toxicol Environ Health A Date: 2002-10-25
Authors: Stephen Newman; William D Bennett; Martyn Biddiscombe; Sunalene G Devadason; Myrna B Dolovich; John Fleming; Sabine Haeussermann; Claudius Kietzig; Philip J Kuehl; Beth L Laube; Knut Sommerer; Glyn Taylor; Omar S Usmani; Kirby L Zeman Journal: J Aerosol Med Pulm Drug Deliv Date: 2012-12 Impact factor: 2.849
Authors: David C Chalupa; Paul E Morrow; Günter Oberdörster; Mark J Utell; Mark W Frampton Journal: Environ Health Perspect Date: 2004-06 Impact factor: 9.031