An Online Measurement Approach to Monitor the Deposition of Diesel Exhaust Particles on Lung Cells In Vitro

Diesel exhaust particles (DEPs) can deposit onto the respiratory epithelial surface upon inhalation. The quantification of DEP deposition on cells is important for understanding dose-response relationships within tissues. However, continuous, nondestructive methods for monitoring DEP deposition on cells remain challenging. We investigated a miniaturized thermosensitive detection system (CalorQuanti) and integrated it into the VITROCELL Cloud Alpha system, the so-called Cloud Alpha/CalorQuanti, to combine cell exposure to particles at the air-liquid interface (ALI) and online particle monitoring on cells. The Cloud Alpha/CalorQuanti demonstrates uniform particle deposition, providing the basis for online monitoring of particles on cells. With low detection limits (93 to 415 ng/cm²) for gold nanoparticles (AuNPs, as test material) and DEPs, the device showed strong positive relationships (R² ≥ 0.95) between particle concentrations measured and thermal signal intensities generated on cells under dry and humid conditions. It also possesses the versatility to optimize online particle detection on cells by adjusting measurement parameters to balance sensitivity and phototoxicity. The Cloud Alpha/CalorQuanti allows exposure to aerosolized DEPs at ALI while providing sensitive monitoring and quantification of DEP deposition on cells. This device is useful for monitoring combustion-derived carbon-based particle exposure on cells following laboratory simulation and field exposures, advancing environmental health research.