Direct fluorescent labeling for efficient biological assessment of inhalable particles

Abstract

Labeling of aerosol particles with a radioactive, magnetic, or optical tracer has been employed to confirm particle localization in cell compartments, which has provided useful evidence for correlating toxic effects of inhaled particles. However, labeling requires several physicochemical steps to identify functionalities of the inner or outer surfaces of particles, and moreover, these steps can cause changes in size, surface charge, and bioactivity of the particles, resulting in misinterpretations regarding their toxic effects. This study addresses this challenging issue with a goal of introducing an efficient strategy for constantly supplying labeled aerosol particles in a single-pass configuration without any pre-or post-physicochemical batch treatments of aerosol particles. Carbon black (CB, simulating combustion-generated soot) or calcium carbonate (CC, simulating brake-wear fragments) particles were constantly produced via spark ablation or bubble bursting, respectively. These minute particles were incorporated with fluorescein isothiocyanate-poly(ethylene glycol) 2-aminoethyl ether acetic acid solution at the orifice of a collison atomizer to fabricate hybrid droplets. The droplets successively entered a diffusion dryer containing 254-nm UV irradiation; therefore, the droplets were dynamically stiffened by UV to form fluorescent probes on particles during solvent extraction in the dryer. Particle size distributions, morphologies, and surface charges before and after labeling were measured to confirm fluorescence labeling without significant changes in the properties. In vitro assays, including confocal imaging, were conducted to confirm the feasibility of the labeling approach without inducing significant differences in bioactivity compared with untreated CB or CC particles. ARTICLE HISTORY

Combustion-derived particles inhibit in vitro human lung fibroblast-mediated matrix remodeling

“…CB is regularly synthesized and used in the global industry market, where employers are exposed to concentrations as high as 650 µg/cm 3 [ 16 ]. In addition, the particles are representative for environmental CDPs to which humans are typically exposed and are often employed as a simplified model for soot or black carbon [ 17 ]. A major challenge is the use of relevant particle concentrations, since in vivo exposure cannot be converted directly to in vitro concentrations [ 18 , 19 ].…”

Modified Aerotaxy for the Plug-in Manufacture of Cell-Penetrating Fenton Nanoagents for Reinforcing Chemodynamic Cancer Therapy

“…Motivated by the above discussions, this study designed and constructed a modified AT system through a serial connection of electrically operable aerosol dispensers and a heated flow reactor to manufacture Mn–Fe spike decorated amorphous CaCO 3 (denoted as Mn–Fe CaCO 3 (AT)) and SiO 2 (denoted as Mn–Fe CaCO 3 (AT)) nanoagents for chemodynamic cancer therapies in a single-pass, continuous configuration, unlike multistep wet chemical processes (Table S1). The modified AT used a spark plasma to ablate the transition metals (Mn and Fe) and a mechanical spray to supply amorphous biocompatible CaCO 3 and SiO 2 nanobeads as a digital manufacture platform − to generate Mn–Fe CaCO 3 and Mn–Fe SiO 2 composite precursors for the in-flight epitaxial growth of anisotropic Mn–Fe oxides (MnFe 2 O 4 ) on nanobeads. The resulting Mn–Fe CaCO 3 (AT) and Mn–Fe SiO 2 (AT) were assessed as biofunctional nanoagents for Fenton reaction-induced cancer treatment (i.e., chemodynamic therapy from hydroxyl radicals that lead to high oxidative stress in tumor cells).…”