Effect of MWCNT surface and chemical modification on in vitro cellular response

Abstract

The aim of this study was to evaluate the impact of multi-walled carbon nanotubes (MWCNTs with diameter in the range of 10–30 nm) before and after chemical surface functionalisation on macrophages response. The study has shown that the detailed analysis of the physicochemical properties of this particular form of carbon nanomaterial is a crucial issue to interpret properly its impact on the cellular response. Effects of carbon nanotubes (CNTs) characteristics, including purity, dispersity, chemistry and dimension upon the nature of the cell environment–material interaction were investigated. Various techniques involving electron microscopy (SEM, TEM), infrared spectroscopy (FTIR), inductively coupled plasma optical emission spectrometry, X-ray photoelectron spectroscopy have been employed to evaluate the physicochemical properties of the materials. The results demonstrate that the way of CNT preparation prior to biological tests has a fundamental impact on their behavior, cell viability and the nature of cell–nanotube interaction. Chemical functionalisation of CNTs in an acidic ambient (MWCNT-Fs) facilitates interaction with cells by two possible mechanisms, namely, endocytosis/phagocytosis and by energy-independent passive process. The results indicate that MWCNT-F in macrophages may decrease the cell proliferation process by interfering with the mitotic apparatus without negative consequences on cell viability. On the contrary, the as-prepared MWCNTs, without any surface treatment produce the least reduction in cell proliferation with reference to control, and the viability of cells exposed to this sample was substantially reduced with respect to control. A possible explanation of such a phenomenon is the presence of MWCNT’s agglomerates surrounded by numerous cells releasing toxic substances.

Evaluation of uptake, cytotoxicity and inflammatory effects in respiratory cells exposed to pristine and ‐OH and ‐COOH functionalized multi‐wall carbon nanotubes

“…The presence of high amounts of MWCNTs‐COOH inside cells in big cytoplasmic vesicles confirms the high cell uptake for carboxylated MWCNTs observed in our previous study (Ursini et al ., ) and is in agreement with the studies of Fraczek‐Szczypta et al . () and Zhang et al (). The higher uptake of COOH‐functionalized MWCNTs and their accumulation into cytoplasm could also explain the high inflammatory response found in A549 cells after 24‐h exposure to such CNTs.…”

“…Higher cytotoxic and genotoxic effects for the functionalized MWCNTs were found in some studies (Magrez et al ., ; Coccini et al , ; Patlolla et al ., ; Zhang et al ., ). Otherwise other studies demonstrated that the ‐COOH functionalization process decreases MWCNTs toxicity (Fraczek‐Szczypta et al ., , Hamilton et al, , Liu et al , , Visalli et al , ). Pulmonary toxicity and an inflammatory response after exposure to pristine and ‐NH 2 and ‐COOH functionalized MWCNTs were found in vivo in rats (Roda et al , ).…”

Degradation Behavior of Electrospun PLA and PLA/CNT Nanofibres in Aqueous Environment

“…Many authors have tackled this problem suggesting negative influence on cell culture and living organisms [36][37][38], though an agreement was not achieved in this matter. What should be noted is the fact that numerous researchers claim that functionalised MWCNTs are less toxic and only slightly affect cells viability [39][40][41].…”

Biological response to purification and acid functionalization of carbon nanotubes

“…Another study showed that MWCNTf induced a reduced cytotoxicity but a slight increase of inflammation and oxidative stress (Zhang et al 2012). Lastly, based on Fraczek-Szczypta et al work (Fraczek-Szczypta et al 2012), the cytotoxicity of MWCNTf remains globally unchanged compared to pristine MWCNT while they have a tendency to decrease cell proliferation.…”