Table 2 List of some toxic effects of carbon nanotubes and associated physiochemical character and tests
From: Toxicity of nanoparticles_ challenges and opportunities
Physiochemical character | CNT type | Test cell/organism | Toxic effects | Ref. |
|---|---|---|---|---|
Contaminants | Commercial SWCNTs and MWCNTs with high content of Fe, Co, Mo and Ni | NR8383; A549 | dose and time dependent increase of intracellular ROS and decrease of mitochondrial membrane potential | (Pulskamp et al. 2007) |
Surface charge and modifications | acid-treated, water-soluble SWCNTs | HMMs | Are less aggregated in lysosomes and cytoplasm and cause no significant changes in cell viability or structure. | (Porter et al. 2009) |
Shape | pristine SWCNTs; oxidized SWCNTs | HUVEC | functionalized and pristine SWCNTs have limited cytotoxicity | (Fubini et al. 2010) |
asbestos-like MWCNTs | Normal mice | length-dependent inflammation and formation of granulomas | (Poland et al. 2008) | |
tangled CNTs; needle-like CNTs | human primary macrophages | tangled CNTs are swallowed into cells; needle-like CNTs activate secretion of IL-1R and IL-1β | (Palomaki et al. 2011) | |
Length | MWCNTs 500 nm to 5 μm | THP-1; rat | average length of 825 nm induce higher inflammation than those with an average length of 220 nm | (Sato et al. 2005) |
MWCNTs: length 5 to 15 μm, diameter 20-60 nm; SWCNTs: length 5 to 15 μm, diameter < 2 nm | A549; THP-1; normal mice | long and thick MWCNTs induce the strongest DNA damage similar SWCNTs caused little effect | (Yamashita et al. 2010) | |
long MWCNTs 1 to 20 μm | p53+/ mice | Long MWNTs can form fibrous or rod-shaped particles of around 10–20 μm (μm) and induce mesothelioma | (Takagi et al. 2008) | |
Number of layers | Pristine graphene | RAW 264.7 | depletion of the mitochondrial membrane potential and increase of intracellular ROS and apoptosis. | (Li et al. 2012) |
SWCNTs; MWCNTs diameters 10 to 20 nm | alveolar macrophage | SWCNTs > MWCNTs | (Jia et al. 2005) | |
Agglomeration | agglomerated SWCNTs; better dispersed SWCNT bundles CNT agglomerates; CNT bundles | SPC; DRG MSTO-211H | highly agglomerated SWCNTs significantly decrease the overall DNA content | (Belyanskaya et al. 2009) |
suspended CNT-bundles are less cytotoxic than asbestos, rope-like agglomerates | (Wick et al. 2007) |