Low-Field Magnetic Deposition of Combustion Generated Aerosol: A Novel in vitro Exposure Technique

AAMIR D. ABID (1) and Ian Kennedy (1)

(1) University of California, Davis

     Abstract Number: 158
     Last modified: November 6, 2009

Abstract
In the past, in vitro studies have been used to investigate the toxicity of airborne pollutants utilizing an electrostatic particle deposition technique onto an air-liquid interface. Particles are charged using an ion source such as a corona discharge. Some difficulties in this technique include (i) a corona discharge that generates ozone which is known to elicit a toxic response in cell cultures, (ii) the solubility of charged particles that may change with varying surface charge, (iii) a size bias so that the particles deposited as ultrafine particles have a higher mobility compared to coarse particles and (iv) small particles have low charging probability where as larger particles can easily obtain multiple charges. To address these challenges of electrostatic deposition , this work uses a magnetic field to deposit particles onto cells. The inherent advantage of using magnetic fields to deposit magnetic particles onto a air-liquid interfaces is that the magnetization of the particles is mass dependent and unaggregated size selected particle deposition can be achieved. Iron oxide nanoparticles are synthesized using a H2/Air diffusion flame. The particle are collected at increasing heights above the burner using low-field permanent magnets. The particle morphology is characterized using TEM and the particle size distribution is measured using dynamic light scattering. At low heights above the burner, the particles deposit onto the collection surface with minimal aggregation. At higher heights the particles self assemble into long chains. This study has a potential to investigate the toxicity of a broad range of materials by coating the magnetic core with a shell of material that is of environmental interest, including other non-magnetic oxides.