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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.


Related in: MedlinePlus

TEM photomicrograph of MWCNT
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Fig6: TEM photomicrograph of MWCNT

Mentions: The Raman spectra of non-functionalised CNTs are shown in Fig. 5a. The spectrum of carbon structure contains two main bands: the G-band (1,606 cm−1—MWCNT), which is assigned to the E2g C–C (sp2-bonded) stretching mode of a well-ordered graphitic structure and the D-band (1,312 cm−1 for MWCNT), attributed to the A1g (sp3-bonded) stretching mode, resulting from the presence of a disordered structure or lattice defects in the graphite structure (substitutional heteroatoms, vacancies or chemically bonded heteroatoms). The intensity ratio of the D-line (ID) to the G-line (IG) in Raman spectra is a useful parameter to evaluate the structural ordering of carbon materials, including carbon nanoforms. A high ID/IG ratio means the presence of defects inside the carbon layers. This parameter equals 2.0 for MWCNTs. This high value for MWCNTs indicates that the degree of crystalline perfection for this type of nanotube is distinctly lower. The bands at 2,623 cm−1 (G′ band) for MWCNTs constitute an overtone of the D band. Due to such a highly defective MWCNT structure, it is more susceptible to the acids’ oxidative mixture. The length of MWCNT after chemical treatment (MWCNT-F) generally decreased (Fig. 7) in comparison to the pristine MWCNT (Fig. 6). Moreover, some surface changes such as destruction of the graphene layers were observed (Fig. 8, arrows). Such changes were not observed for as-prepared MWCNT.Fig. 7


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)

TEM photomicrograph of MWCNT
© Copyright Policy
Related In: Results  -  Collection

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

Fig6: TEM photomicrograph of MWCNT
Mentions: The Raman spectra of non-functionalised CNTs are shown in Fig. 5a. The spectrum of carbon structure contains two main bands: the G-band (1,606 cm−1—MWCNT), which is assigned to the E2g C–C (sp2-bonded) stretching mode of a well-ordered graphitic structure and the D-band (1,312 cm−1 for MWCNT), attributed to the A1g (sp3-bonded) stretching mode, resulting from the presence of a disordered structure or lattice defects in the graphite structure (substitutional heteroatoms, vacancies or chemically bonded heteroatoms). The intensity ratio of the D-line (ID) to the G-line (IG) in Raman spectra is a useful parameter to evaluate the structural ordering of carbon materials, including carbon nanoforms. A high ID/IG ratio means the presence of defects inside the carbon layers. This parameter equals 2.0 for MWCNTs. This high value for MWCNTs indicates that the degree of crystalline perfection for this type of nanotube is distinctly lower. The bands at 2,623 cm−1 (G′ band) for MWCNTs constitute an overtone of the D band. Due to such a highly defective MWCNT structure, it is more susceptible to the acids’ oxidative mixture. The length of MWCNT after chemical treatment (MWCNT-F) generally decreased (Fig. 7) in comparison to the pristine MWCNT (Fig. 6). Moreover, some surface changes such as destruction of the graphene layers were observed (Fig. 8, arrows). Such changes were not observed for as-prepared MWCNT.Fig. 7

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