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

Fraczek-Szczypta A, Menaszek E, Syeda TB, Misra A, Alavijeh M, Adu J, Blazewicz S - J Nanopart Res (2012)

Bottom Line: 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.A possible explanation of such a phenomenon is the presence of MWCNT's agglomerates surrounded by numerous cells releasing toxic substances.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomaterials, Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, Al Mickiewicza 30, 30-059 Kraków, Poland.

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.

No MeSH data available.


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SEM photomicrographs of cells in contact with MWCNT-Fs. Magnification ×500 (a), ×20,000 (b)
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Fig16: SEM photomicrographs of cells in contact with MWCNT-Fs. Magnification ×500 (a), ×20,000 (b)

Mentions: The interaction between MWCNTs and macrophages was also analysed using SEM (Figs. 14, 15, 16, 17). Depending on the types of CNT, a major difference was observed in the morphology of cells. The morphology of macrophages, especially in contact with MWCNTs (Fig. 15), was comparable to cells in the control sample (Fig. 14) (macrophages without CNTs). For this sample, the cells have a round shape in contrast to macrophages in contact with MWCNT-F, where cells have an elongated and fusiform shape (Fig. 16). For samples containing MWCNT-NHs macrophages, the majority display a round shape although fusiform shape cells were observed as well (Fig. 17). In the case of MWCNTs and MWCNT-NHs, the numbers of cells were higher than in cultures containing MWCNT-Fs. One of the reasons might be the presence of CNT agglomerates, especially in the samples containing MWCNTs. In this case, the majority of nanotubes accumulate to form agglomerates and thus leave the areas “free” of these materials so that the cells can proliferate as in the control sample. A better dispersion of MWCNT-Fs and difference in their shape in comparison to as-prepared MWCNTs make this material easier to transfer into the cells. It is also probable that the processes associated with transport of CNTs into the cells, e.g. phagocytosis, are more active than those connected with cell division. Another reason for the lowering of cell proliferation and distortion in cell shape for cells in contact with MWCNT-F, in comparison with MWCNTs and the control sample, may be a negative impact of nanomaterials on the normal physiological processes of these cells. Cells with apparently damaged membranes after contact with the purified nanotubes (MWCNT-F) were found under microscopy (Fig. 12b, arrow). Such a case was noted for cells filled with a large amount of CNTs. The presence of MWCNT-Fs in the cytoplasm of cells is shown by the SEM photomicrograph (Fig. 16b). The photomicrograph clearly shows that MWCNT-Fs are located across the cells membrane, which confirms the presence of nanotubes inside the cells. A similar behaviour of nanotubes has also been reported in the literature (Hu et al. 2010; Hirano et al. 2008).Fig. 14


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

Fraczek-Szczypta A, Menaszek E, Syeda TB, Misra A, Alavijeh M, Adu J, Blazewicz S - J Nanopart Res (2012)

SEM photomicrographs of cells in contact with MWCNT-Fs. Magnification ×500 (a), ×20,000 (b)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3473194&req=5

Fig16: SEM photomicrographs of cells in contact with MWCNT-Fs. Magnification ×500 (a), ×20,000 (b)
Mentions: The interaction between MWCNTs and macrophages was also analysed using SEM (Figs. 14, 15, 16, 17). Depending on the types of CNT, a major difference was observed in the morphology of cells. The morphology of macrophages, especially in contact with MWCNTs (Fig. 15), was comparable to cells in the control sample (Fig. 14) (macrophages without CNTs). For this sample, the cells have a round shape in contrast to macrophages in contact with MWCNT-F, where cells have an elongated and fusiform shape (Fig. 16). For samples containing MWCNT-NHs macrophages, the majority display a round shape although fusiform shape cells were observed as well (Fig. 17). In the case of MWCNTs and MWCNT-NHs, the numbers of cells were higher than in cultures containing MWCNT-Fs. One of the reasons might be the presence of CNT agglomerates, especially in the samples containing MWCNTs. In this case, the majority of nanotubes accumulate to form agglomerates and thus leave the areas “free” of these materials so that the cells can proliferate as in the control sample. A better dispersion of MWCNT-Fs and difference in their shape in comparison to as-prepared MWCNTs make this material easier to transfer into the cells. It is also probable that the processes associated with transport of CNTs into the cells, e.g. phagocytosis, are more active than those connected with cell division. Another reason for the lowering of cell proliferation and distortion in cell shape for cells in contact with MWCNT-F, in comparison with MWCNTs and the control sample, may be a negative impact of nanomaterials on the normal physiological processes of these cells. Cells with apparently damaged membranes after contact with the purified nanotubes (MWCNT-F) were found under microscopy (Fig. 12b, arrow). Such a case was noted for cells filled with a large amount of CNTs. The presence of MWCNT-Fs in the cytoplasm of cells is shown by the SEM photomicrograph (Fig. 16b). The photomicrograph clearly shows that MWCNT-Fs are located across the cells membrane, which confirms the presence of nanotubes inside the cells. A similar behaviour of nanotubes has also been reported in the literature (Hu et al. 2010; Hirano et al. 2008).Fig. 14

Bottom Line: 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.A possible explanation of such a phenomenon is the presence of MWCNT's agglomerates surrounded by numerous cells releasing toxic substances.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomaterials, Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, Al Mickiewicza 30, 30-059 Kraków, Poland.

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.

No MeSH data available.


Related in: MedlinePlus