An In Vitro Lung System to Assess the Proinflammatory Hazard of Carbon Nanotube Aerosols.

Hana Barosova,Dedy Septiadi,Barbara Rothen-Rutishauser,Alke Petri-Fink,Vicki Stone,Bedia Begum Karakocak

doi:10.3390/ijms21155335

Abstract

In vitro three-dimensional (3D) lung cell models have been thoroughly investigated in recent years and provide a reliable tool to assess the hazard associated with nanomaterials (NMs) released into the air. In this study, a 3D lung co-culture model was optimized to assess the hazard potential of multiwalled carbon nanotubes (MWCNTs), which is known to provoke inflammation and fibrosis, critical adverse outcomes linked to acute and prolonged NM exposure. The lung co-cultures were exposed to MWCNTs at the air-liquid interface (ALI) using the VITROCELL® Cloud system while considering realistic occupational exposure doses. The co-culture model was composed of three human cell lines: alveolar epithelial cells (A549), fibroblasts (MRC-5), and macrophages (differentiated THP-1). The model was exposed to two types of MWCNTs (Mitsui-7 and Nanocyl) at different concentrations (2–10 μg/cm2) to assess the proinflammatory as well as the profibrotic responses after acute (24 h, one exposure) and prolonged (96 h, repeated exposures) exposure cycles. The results showed that acute or prolonged exposure to different concentrations of the tested MWCNTs did not induce cytotoxicity or apparent profibrotic response; however, suggested the onset of proinflammatory response.

Highlights

Carbon nanotubes (CNTs) exhibit remarkable features, such as thermal stability, electrical conductivity, and outstanding mechanical durability, and are one of the most widely used nanomaterials (NMs) [1], especially in the fields of energy, electronics, and material composites
To estimate the amount and form of test materials deposited on the cells, transmission electron microscopy (TEM) grids were placed in the VITROCELL® Cloud exposure chamber during the material aerosolization and subsequently analyzed using TEM
TThhee rreepprreesseennttaattiivvee TTEEMM iimmaaggeess of the deposited samples display the morphological difffferences among the two multiwalled carbon nanotubes (MWCNTs) samples, i.e., Mitsui-7 and Nanocyl

Summary

Introduction

Carbon nanotubes (CNTs) exhibit remarkable features, such as thermal stability, electrical conductivity, and outstanding mechanical durability, and are one of the most widely used nanomaterials (NMs) [1], especially in the fields of energy, electronics, and material composites. The promising potential of CNTs in industrial applications increases the demand for CNT production This high demand is expected to lead to increased contamination of the natural eco-system as well as human exposure, which can potentially occur throughout the NMs life cycle, starting from production to their final disposal. CNTs are made of rolled-up graphene sheets—graphene cylinders, typically limited to a few nanometers in diameter, but their length can range from a few micrometers to millimeters [4]. This unique geometry of relatively small diameter and the enormous length, the needle-like shape, have drawn comparisons with asbestos [5]. There are two main classes of CNTs: single-walled carbon nanotubes (SWCNTs), which consist of one graphene cylinder, and multiwalled carbon nanotubes (MWCNTs) comprises two or more of these graphene cylinders [6]

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