Assessment of Scanning Mobility Particle Sizer (SMPS) for Online Monitoring of Delivered Dose in an in Vitro Aerosol Exposure System
SRIPRIYA NANNU SHANKAR, Kiran Mital, Eric Le, Gregory S. Lewis, Arantzazu Eiguren-Fernandez, Tara Sabo-Attwood, Chang-Yu Wu,
University of Florida Abstract Number: 292
Working Group: Instrumentation and Methods
AbstractReal-time monitoring of dose delivered in a controlled manner is an important consideration for assessing aerosol toxicity. To address this, we propose the use of the Scanning Mobility Particle Sizer (SMPS) as a tool to estimate the delivered dose through the Dosimetric Aerosol in Vitro Inhalation Device (DAVID), which efficiently deposits particles after particle size amplification by water vapor condensation. We aerosolized CuO nanoparticles (25-55 nm) suspended in alcohol at different concentrations (0.01-10 mg/mL) for 5-30 min using a Collison nebulizer. Diluting the generated aerosols with air at a ratio of 1:3 (setup 1) yielded concentrations in the range of 3.65×10
5±5.38×10
5 – 1.76×10
6±1.58×10
5 #/cm
3. On further diluting 1 LPM exiting setup 1 with 4.5 LPM of compressed air (setup 2), the concentrations reduced to 2.25×10
4±8.58×10
3 – 1.44×10
5±3.78×10
4 #/cm
3. The deposition efficiencies determined by the ratio of number concentrations of particles exiting and entering DAVID, as measured by the SMPS for setups 1 and 2, were 31.0%±13.0% and 86.9%±8.6%, respectively. The real-time mass dose (Dose
SMPS) was estimated using particle diameter of average volume and number concentration from the SMPS measurements, while the delivered dose (Dose
ICP) was determined from the Cu concentrations analyzed by Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). The averaged ratio of Dose
SMPS:Dose
ICP was 2.1±0.75 for setup 1 and 1.04±0.29 for setup 2, for nebulizer concentrations of 0.1-10 mg/mL. A linear trend was observed for Dose
SMPS vs. Dose
ICP with correlation of >0.99 for setup 1 and >0.89 for setup 2. Our study demonstrates that the SMPS can be used to monitor the delivered dose on a real-time basis. Controlled delivery of mass dose ranging from 0.4±0.02 to 90.3±12.0 μg/cm
2 can be attained within 30 min in a condensation-based particle growth exposure system by adjusting the nebulizer concentrations, aerosolization time, and dilution air.