Potentially, the toxicity of multiwalled carbon nanotubes (MWCNTs) can be reduced in a safe-by-design strategy. We investigated if genotoxicity and pulmonary inflammation of MWCNTs from the same batch were lowered by a) reducing length and b) introducing COOH-groups into the structure. Mice were administered: 1) long and pristine MWCNT (CNT-long) (3.9 μm); 2) short and pristine CNT (CNT-short) (1 μm); 3) CNT modified with high ratio COOH-groups (CNT-COOH-high); 4) CNT modified with low ratio COOH-groups (CNT-COOH-low). MWCNTs were dosed by intratracheal instillation at 18 or 54 μg/mouse (∼0.9 and 2.7 mg/kg bw). Neutrophils numbers were highest after CNT-long exposure, and both shortening the MWCNT and addition of COOH-groups lowered pulmonary inflammation (day 1 and 28). Likewise, CNT-long induced genotoxicity, which was absent with CNT-short and after introduction of COOH groups. In conclusion, genotoxicity and pulmonary inflammation of MWCNTs were lowered, but not eliminated, by shortening the fibres or introducing COOH-groups.

通过安全设计策略可以降低多壁碳纳米管（MWCNT）的毒性。我们研究了 a) 减少长度和 b) 在结构中引入 COOH 基团是否可以降低同批次 MWCNT 的遗传毒性和肺部炎症。给小鼠施用： 1) 长且原始的 MWCNT (CNT-long) (3.9 μm)； 2）短而原始的CNT（CNT-short）（1μm）； 3)高比例COOH基团修饰的CNT(CNT-COOH-high)； 4) 用低比例COOH基团改性的CNT(CNT-COOH-低)。多壁碳纳米管通过气管内滴注给药，剂量为 18 或 54 μg/小鼠（~0.9 和 2.7 mg/kg bw）。长时间暴露于 CNT 后，中性粒细胞数量最高，缩短 MWCNT 和添加 COOH 基团均可降低肺部炎症（第 1 天和第 28 天）。同样，长 CNT 会诱导遗传毒性，而短 CNT 和引入 COOH 基团后则不存在这种遗传毒性。总之，通过缩短纤维或引入 COOH 基团，多壁碳纳米管的遗传毒性和肺部炎症得到降低，但并未消除。