Dry Lung as a Physical Model in Studies of Aerosol Deposition

Abstract

A new physical model was developed to evaluate the deposition of micro- and nanoaerosol particles (NAPs) into the lungs as a function of size and charges. The model was manufactured of a dry, inflated swine lung produced by Nasco company (Fort Atkinson, WI). The dry lung was cut into two lobes and a conductive tube was glued into the bronchial tube. The upper 1-2-mm-thick layer of the lung lobe was removed with a razor blade to expose the alveoli. The lobe was further enclosed into a plastic bag and placed within a metalized plastic box. The probability of aerosol deposition was calculated by comparing the size distribution of NAPs passed through the lung with that of control, where aerosol passed through a box bypassing the lung. Using this new lung model, it was demonstrated that charged NAPs are deposited inside the lung substantially more efficiently than neutral ones. It was also demonstrated that deposition of neutral NAPs well fits prediction of the Multiple-Path Particle Dosimetry (MPPD) model developed by the Applied Research Associates, Inc. (ARA).

Antitumor Effect of Bleomycin Nanoaerosol in Murine Carcinoma Model

“…Its operation is based on electrohydrodynamic spraying of water and ethanol solutions followed by gas-phase neutralization. Nanoaerosol particles (NAPs) generated by this technique bear a few charges on each particle [ 48 ]. Earlier, we showed that charged NAPs were deposited within a dry swine lung model twice as efficiently as neutral NAPs of the same size [ 48 ].…”

Ballistic Penetration of Highly Charged Nanoaerosol Particles through a Lipid Monolayer

“…NAPs from the generator bear several charges on each particle. 10 The size distribution of the NAPs from the generator was characterized by the same SMPS (equipped with an input impactor having a cutoff size of d 50 = 664 nm) after the particles were passed through the soft X-ray charger in order to equilibrate them to the Boltzmann distribution. The mass concentration of NAPs was measured by a piezobalance dust monitor (Kanomax, model 3521, Andover, NJ).…”

“…The distribution of charges on the NAPs thus generated deviates substantially from the Boltzmann distribution in which only a small fraction of NAPs is charged (e.g., ∼40% of NAPs, 100 nm in diameter, have one elementary charge). NAPs from the generator bear several charges on each particle . The size distribution of the NAPs from the generator was characterized by the same SMPS (equipped with an input impactor having a cutoff size of d 50 = 664 nm) after the particles were passed through the soft X-ray charger in order to equilibrate them to the Boltzmann distribution.…”

“…9 We demonstrated that the NAPs generated were not completely neutralized and found that the presence of charges resulted in NAPs being deposited in the lungs more efficiently than neutral particles. 10 Unlike neutral NAPs, charged NAPs interact with the mirror charges induced within the conducting lung fluid and acquire a certain speed from this electrostatic attraction. Therefore, their penetration through the surfactant layer may differ from that of neutral particles.…”

“…Recently, we suggested a new technique for generating NAPs from biological and biologically active substances that is based on the gas-phase neutralization of electrosprayed products . We demonstrated that the NAPs generated were not completely neutralized and found that the presence of charges resulted in NAPs being deposited in the lungs more efficiently than neutral particles …”