Table 1.

The table below summarizes the features of carbon nanotubes and their influence on cytotoxicity.

Aspect.	Condition	Result	116	Reference
Dose	40 μg of SWCNTs aspirated by mouse	Low toxicity	Dose probable to be encountered occupationally	[71]
Method of administration	Intratracheal instillation and inhalation	Alveolar destruction and inflammatory response upon instillation and no inflammatory cells and thickening of the alveolar wall upon inhalation	High doses of MWCNTs used	[73]
Length	5 um vs. 0.7 um MWCNTs injected peritoneally	Mesothelioma formation with long MWCNTs and no mesothelioma with short MWCNTs	-	[76]
Diameter	Macrophage viability upon exposure with <40 nm MWCNTs and 15–40 nm MWCNTs in diameter	No effects on viability with <40 nm MWCNTs and mild toxicity with 15-40 nm MWCNTs	-	[77]
Aggregation	Intratracheal instillation of aggregated and highly dispersed SWCNTs in 1% Pluronic F 108NF to mice	Lung inflammation was induced by aggregated SWCNTs in PBS, while highly dispersed SWCNTs do not cause any inflammation or fibrosis	Very high dose (40 mg) of SWCNTs was used	[79]
Purity	Cytotoxicity of MWCNTs with and without residual iron catalyst on murine alveolar macrophages	Toxic effects exerted only after treatment with unpurified MWCNTs	-	[81]
Surface functionalization	Unmodified and carboxyl modified MWCNTs instilled in C57BL/6 mouse lungs	Carboxyl functionalization reduces inflammation and lung pathologies	Dispersion status was not affecting the results, since both samples were well dispersed with surfactant	[78]
Method of detection	Toxicity of SWCNTs was tested on A549 cell line with Coomassie Blue, Alamar BlueTM, Neutral Red, MTT and WST-1	Employment of different method yielded various results	-	[83]