Всего тела наночастиц Воздействие аэрозолей при вдыхании
Summary
Всего тела аэрозольной ингаляции наночастиц воздействия объекте предполагалось наноразмерного диоксида титана (TiO<sub> 2</sub>) Исследования ингаляции токсикологии. Эта система обеспечивает нано-TiO<sub> 2</sub> Аэрозоль атмосферы теста, которые: 1) стационарная концентрация массы; 2) однородной композиции, свободной от загрязнений и 3) стабильное распределение частиц по размерам в течение аэрозоля.
Abstract
Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter < 200 nm and a geometric standard deviation σg < 2.5 5. The generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size 6, which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria 5.
A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m3 whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm3) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m3). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpre and Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is sampling flowrate (m3/min), and t is the sampling time (minute). The chamber pressure, temperature, relative humidity (RH), O2 and CO2 concentrations were monitored and controlled continuously. Nano-TiO2 aerosols collected on Nuclepore filters were analyzed with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis.
In summary, we report that the nano-particle aerosols generated and delivered to our exposure chamber have: 1) steady mass concentration; 2) homogenous composition free of contaminants; 3) stable particle size distributions with a count-median aerodynamic diameter of 157 nm during aerosol generation. This system reliably and repeatedly creates test atmospheres that simulate occupational, environmental or domestic ENM aerosol exposures.
Protocol
Representative Results
Discussion
Мы собрали и описали здесь, в всего тела аэрозолей наночастиц системы вдыхание. Функциональность системы была подтверждена с государством в самых современных методов аэрозолей наночастиц характеристики. С аэрозоль нового поколения системы наночастиц, эта система вдыхания может обес…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Список подтверждений и источников финансирования.
NIH-ES015022 и ES018274 (TRN)
NSF-соглашение о сотрудничестве 1003907 (VCM)
Materials
| Name of Reagent/Material | Company | Catalog Number | Comments |
| Inhalation exposure system | TSE Systems GmbH, Bad Homburg, Germany | ||
| Air monitoring system | TSE Systems GmbH, Bad Homburg, Germany | ||
| Titanium dioxide Aeroxide P25 | Evonik, Germany | ||
| Scanning mobility particle sizer-3936L75 | TSI Inc., Shoreview, MN | ||
| Electric low pressure impactor, Standard 10 LPM | Dekati, Tampere, Finland | ||
| Ultra Micro Balance, XP2U | METTLER TOLEDO, Switzerland | ||
| Field Emission Scanning Electron Microscope-S-4800 | Hitachi, Japan | ||
| Energy dispersive X-ray analysis | Princeton Gamma-Tech, Rocky Hill, N.J. | ||
| Nuclepore polycarbonate filters | Whatman, Clinton, PA | ||
| PTFE membrane filters | Pall corporation, Ann Arbor, Michigan |
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