Biomembrane damage caused by exposure to multi-walled carbon nanotubes

Abstract

-Carbon nanotubes (CNTs) have potential as not only electrical materials but also biomedical devices. However, some findings have been reported indicating that the use of CNTs is accompanied by a risk of the development of certain diseases such as pulmonary fibrosis and pleura mesothelioma; and one of the reasons for this risk may be macrophage cell death. In the present study, to elucidate the mechanism of macrophage cell death by CNTs, we focused on biomembrane damage caused by multi-walled CNTs (MWCNTs). When the distribution of MWCNTs in RAW264 cells was observed under a light microscope, MWCNTs were located on the surface of the plasma membrane; and a portion of them seemed to stick into it. The acute cytotoxicity toward RAW264 cells was examined by performing the LDH cytotoxic test, and LDH release was detected after exposure to 100 μg/ml CNT. To examine the physical damage to biomembranes by CNT exposure, we conducted a calcein release assay using calceinencapsulated liposomes. The results indicated that an increase in the permeability of the lipid bilayer was induced by MWCNTs. The present study thus demonstrated for the first time that a high concentration of MWCNTs was cytotoxic to macrophages and suggested that the direct physical perturbation of biomembranes by MWCNTs plays a role in this activity.

Carbon Nanotubes: An Emerging Drug Carrier for Targeting Cancer Cells

“…It was reported that length of MWCNTs was found to exert effects on the biomembranes; when the distribution of MWCNTs (3–14  μ m length) in RAW264 cells was observed under a light microscope, MWCNTs were located on the surface of the plasma membrane and a portion of them seemed to be stucked on it which tends to increase the permeability defects of the plasma membrane lipid bilayer while shorter (1.5  μ m) MWCNTs were significantly less toxic [168, 169]. In a study, interference of CNTs with cytoskeleton was investigated by Shvedova et al, and exposure of cultured human epidermal keratinocytes (HaCaT) to SWCNTs induces oxidative stress and results into loss of cell viability, indicating that dermal exposure to CNTs may lead to these altered skin conditions [170].…”

Effects of lipopolysaccharide, multiwalled carbon nantoubes, and the combination on lung alveolar epithelial cells

“…Both of these studies also showed increased levels of inflammatory cytokines TNFα, IL‐1β, IL‐6 in the lungs and bronchoalveolar lavage fluid, and these changes were time‐ and dose‐dependent. In vitro s tudies using lung cells showed that MWCNT upregulated α‐smooth muscle actin (α‐SMA) and induced transition of epithelial cells toward fibroblasts via the TGFβ/Smad pathway (Chen et al, ), promoted surface morphological changes (Cavallo et al, ; Shimizu et al, ), and altered the expression of 106 proteins involved in cell proliferation, stress, and cellular skeleton organization (Ju et al, ). Fibrotic lesions in the interstitium of lungs is a typical response following inhalation of particles or fibers, however the exact cellular and molecular mechanism of MWCNT‐induced pulmonary fibrosis still largely remains unknown.…”

Nanotoxicology: Contemporary Issues and Future Directions

“…Simulation studies suggest that insertion of CNTs in plasma membrane results in formation of pores through which solvated ions can pass [ 308 ]. Experimental studies using liposomes and RAW 264.7 cells also confi rmed membrane damaging potential of MWCNTs [ 309 ]. The disruption of plasma membrane has also been documented in electron microscopy.…”