AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
A Novel Device for Cell Exposure at the Air-Liquid Interface
Mika Ihalainen, Pasi, I Jalava, Kari Kuuspalo, Maija-Riitta Hirvonen, JORMA JOKINIEMI, University of Eastern Finland, Kuopio, Finland
Abstract Number: 305 Working Group: Health Related Aerosols
Abstract Inhalation exposure is the main route causing health effects by the air pollutants. Air-liquid interface (ALI) in-vitro exposure mimics most realistically real life conditions. In ALI devices it is crucial to know the dose for the cells accurately. The dose from inhaled particles is determined by particle size and concentration at the air-liquid interface. The most important natural deposition mechanisms at the air-liquid interface are interception, impaction, gravitational settling and diffusion. However, diffusion is strongly dependent on particle size and thus dose determination becomes difficult. Also deposition by diffusion is very inefficient for particles larger than about 10 nm. Hence it is not possible to get high enough dose for toxicological studies by diffusion in most applications. Deposition by thermophoresis does not depend much on particle size up to several hundred nanometers. Thus from various initial size distributions it is fairly easy to determine the deposited amount of particles by thermophoresis.
We have designed a novel ALI device where it is easy to control flow rates, temperature and relative humidity. Deposition of various nanoparticles has been determined by collecting particles on foils for subsequent microscopic analysis. The aerosols were characterized with the scanning mobility particle sizer (SMPS) prior the ALI device. A model describing the deposition of the ALI device was constructed and validated with the experimental results. The results show that the online data (SMPS) estimated quite well the size distribution of the deposited particles (SEM).
Our ALI device shows several advantages compared to existing commercial devices as high deposition efficiency, uniform deposition over the whole cell area, reliable determination of the exposure dosage and possibilities to select parameters without compromising the well-being and viability of the target cells. So far the ALI device has been used to expose cells with silver and zinc oxide nanoparticles and wood smoke.