“…4a) can be distinguished, i.e. at 530.6 eV corresponding to oxidation of nickel into NiO, at 532.9 eV corresponding to functionalised oxygen-containing groups, such as carboxylate, hydroxyl, quinoneand lactone (Ohta et al 1974; Vigolo et al 2010), at 534.6 eV attributed to adsorbed oxygen or hydroxyl groups (alcohols, phenol, hydroquinone) (Vigolo et al 2010) on the CNTs surface and at 536.2 eV.Fig. 4XPS spectra for MWCNT a and MWCNT-F b …”
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.
“…4a) can be distinguished, i.e. at 530.6 eV corresponding to oxidation of nickel into NiO, at 532.9 eV corresponding to functionalised oxygen-containing groups, such as carboxylate, hydroxyl, quinoneand lactone (Ohta et al 1974; Vigolo et al 2010), at 534.6 eV attributed to adsorbed oxygen or hydroxyl groups (alcohols, phenol, hydroquinone) (Vigolo et al 2010) on the CNTs surface and at 536.2 eV.Fig. 4XPS spectra for MWCNT a and MWCNT-F b …”
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.
“…First, pristine DWCNTs (P-DWCNT) were oxidized using a HNO 3 treatment. Such an operation is known to eliminate metallic particles resulting from the synthesis procedure but also to generate functional groups, in particular carboxylic groups [44,45]. Then amino groups are grafted using hexane diamine (HDA) and EDC as coupling agent (Fig.…”
A spectroscopic study of the amino functionalization of double-walled carbon nanotube (DWCNT) is performed. Original experimental investigations by near edge X-ray absorption fine structure spectroscopy at the C and O K-edges allow one to follow the efficiency of the chemistry during the different steps of covalent functionalization. Combined with Raman spectroscopy, the characterization gives a direct evidence of the grafting of amino-terminated molecules on the structural defects of the DWCNT external wall, whereas the internal wall does not undergo any change. Structural and mechanical investigation of the amino functionalized DWCNT / epoxy composites show coupling between epoxy molecules and the DWCNTs. Functionalization improves the interface between aminofunctionalized DWCNT and the epoxy molecules. The electrical transport measurements indicate a percolating network formed only by inner metallic tubes of the DWCNTs. The activation energy of the barriers between connected metallic tubes is determined around 20 meV.
“…Modern modifications of multiwalled carbon nanotubes (MWCNTs) involve single to several steps of the external walls modification, called exohedral functionalization, which depends on further applications of the prepared material [2,[14][15][16][17][18]. The oxidation process is the simplest and most common single-step of the outer wall functionalization, leading to the introduction of the functional groups on their outer walls, which can be used as a linkers for further more sophisticated modifications [19][20][21][22][23]. The silanization process is the effective procedure for further modification of the physical and chemical properties of multiwalled carbon nanotubes for present polymer nanocomposites development [7,24].…”
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