Toxicity in vitro of some silicon carbides and silicon nitrides: Whiskers and powders

Abstract

The objectives of this work were to investigate the toxicity of silicon carbide whiskers and powders and silicon nitride whiskers and powders and to compare their toxicity with the toxicity of crocidolite. The effects studied were inhibition of the cloning efficiency of V79 cells, formation of DNA strand breaks by means of a nick translation assay, formation of oxygen radicals in three different assays, and the ability to stimulate neutrophils to produce hydroxyl radicals. All materials showed concentration‐dependent inhibition of the cloning efficiency of V79 cells. The inhibition by the most toxic whiskers was in the same order of magnitude as that of crocidolite. Milled whiskers and powders were less toxic than the whiskers. There was a high DNA breaking potential for crocidolite and four of the silicon carbide whiskers and a rather low one for the other materials. Formation of hydroxyl radicals was found for crocidolite and one of the silicon carbide whiskers. In the neutrophil activation test, there was a great variation in the different materials' abilities to activate neutrophils. There was also a good correlation between chemiluminescence and H2O2 formation. The highest activation was found in neutrophils exposed to two of the silicon carbide whiskers and one milled whisker. The conclusion of the investigation is that some of the ceramic materials studied had damaging biological effects comparable to or greater than those of crocidolite. The results from the investigation clearly imply that caution is needed in the introduction of new ceramic fiber materials, so that the correct precautions and protective devices are used in order to avoid harm to the personnel handling the material. Am. J. Ind. Med. 31:335–343, 1997. © 1997 Wiley‐Liss, Inc.

Magnetometric Evaluation for the Effects of Silicon Carbide Whiskers on Alveolar Macrophages.

“…Recently, some authors reported toxicity of SiC [12][13][14] . In in vitro experiments, toxicity was evaluated by the production of tumor necrosis factor (TNF) 12) and the inhibition of the cloning efficiency of cell lines 13) . In in vivo experiments, Vaugham et al 14) observed histological changes such as multiple pulmonary granulomas with occasionally occluded airways induced by chronic exposure to SiC by transtracheal instillation.…”

“…Recently SiC has been used as a substitute for asbestos, but the toxicity was evaluated insufficiently. Previously, the cytotoxicity of SiC has been reported by some authors [12][13][14] . But there have been few reports concerning the toxicity of this material evaluated by measuring the cell functions.…”

In vitro cellular responses to silicon carbide particles manufactured through the Acheson process: Impact of physico-chemical features on pro-inflammatory and pro-oxidative effects

“…These results mainly underline a potential impact of SiC particle shape on the biological activity, because SiC whiskers (i.e. long and rigid rods of SiC) induce more important biological activity than isotropic SiC particles (Svensson et al, 1997).…”

“…In vivo exposure to whiskers triggers lung inflammation (Cullen et al, 1997), granulomas (Vaughan et al, 1993), bronchoalveolar hyperplasia and severe lung fibrotic changes (Akiyama et al, 2007), while micro-scaled SiC particles were associated to oxidative stress, genotoxic and carcinogenic effects (Cichy, 1989;Svensson et al, 1997;Allen et al, 1995). Moreover, in vitro responses are characterized by significant reactive oxygen species (ROS) generation (Svensson et al, 1997), cytotoxic and genotoxic effects (Svensson et al, 1997;Allen et al, 1995), and stimulation of pro-inflammatory cytokines production like TNFα (Allen et al, 1995;Cullen et al, 1997). These results mainly underline a potential impact of SiC particle shape on the biological activity, because SiC whiskers (i.e.…”

Improvement of the Aluminum Borate Whisker-Mediated Method of DNA Delivery into Rice Callus

“…Furthermore, transgenic plants produced by the SCW method include those of maize (Frame et al, 1994;Petolino et al, 2000), Lolium multifl olum, Lolium perenne, Festuca arundinacea, Agrostis stolonifera (Dalton et al, 1998), and rice (Matsushita et al, 1999). However, SCW can be toxic and mutagenic to organisms, including humans (Vaughan et al, 1991;Svensson et al, 1997). Therefore, we recently developed a safer aluminum borate whisker (ABW)-mediated method of producing transgenic rice plants (Takahashi et al, 2000).…”