Effect of carbon nanotubes on cellular functions in vitro

Abstract

Carbon nanotubes (CNTs) have been shown to affect cell behavior. But how and why the CNTs affect potential differentiation of the attached cells has not been largely known. In this study, multiwalled carbon nanotubes (MWNTs) and graphite (GP) were pressed as compacts. Higher ability of CNTs to adsorb proteins, compared with GP, was shown. Myoblastic mouse cells (C2C12) were cultured and the cell responses to the two kinds of compacts were compared in vitro. Meanwhile, we used cell culture on the culture plate as a control. During the conventional culture, significantly better cell attachment, proliferation, and differentiation of cells on the MWNTs were found. To confirm the hypothesis that the larger amount of protein adsorbed on the CNTs was crucial for this, we made the compacts adsorb more proteins in culture medium with 50% fetal bovine serum (FBS) before cell culture. With the adsorption of the proteins in advance, the increments of the total-protein/DNA and alkaline phosphatase (ALP)/DNA for the MWNTs was respectively as about 11 times and 18 times as the increments of those for GP and the control at both day 4 and day 7. Therefore, the CNTs might induce cellular functions by adsorbing more proteins, which indicated that the CNTs might be a candidate for scaffold material for tissue engineering.

Nanocomposite and Nanostructured Carbon-based Films as Growth Substrates for Bone Cells

“…As a result, graphite compacts allowed the attachment of mouse myoblastic C2C12 cells in significantly lower numbers compared to www.intechopen.com Nanocomposite and Nanostructured Carbon-based Films as Growth Substrates For Bone Cells 387 carbon nanotube compacts, which showed a significantly high capability to adsorb proteins. The C2C12 cells then proliferated more slowly, and contained a lower amount of alkaline phosphatase and total protein (Li et al, 2009a). A similar response was found in human osteosarcoma SaOs-2 cells, which attached and proliferated much worse on graphite than on single-and multi-walled carbon nanotube films .…”

“…However, despite its electrical conductivity, which is usually associated with the stimulatory effects on cell colonization and functioning, unmodified graphite is rather bioinert, i.e., less adhesive for cells . It is due to a relatively low ability of graphite to adsorb cell adhesionmediating proteins from the serum supplement of the culture medium Li et al, 2009a) and also bone morphogenetic proteins (BMP), such as BMP-2, a factor promoting the osteogenic cell differentiation (Li et al, 2009b). As a result, graphite compacts allowed the attachment of mouse myoblastic C2C12 cells in significantly lower numbers compared to www.intechopen.com Nanocomposite and Nanostructured Carbon-based Films as Growth Substrates For Bone Cells 387 carbon nanotube compacts, which showed a significantly high capability to adsorb proteins.…”

“…Carbon nanotubes deposited on various substrates, such as polycarbonate membranes , glass coverslips (Holy et al, 2009), titanium (Terada et al, 2009), silicone rubber (Matsuoka et al, 2009), or pressed in compacts (Li et al, 2009a) markedly improved the adhesion, proliferation and differentiation of cells in cultures on these films in comparison with the non-coated materials or pure graphite. Similarly as in the composites of carbon nanotubes with polymers and ceramics, these favorable effects were mediated by an increased adsorption of specific proteins promoting cell adhesion, growth and differentiation, such as cell adhesion-mediating proteins from the serum of the culture medium , Li et al, 2009a and bone morphogenetic protein-2 (Li et al, 2009b), and particularly by the electrical activity of carbon nanotubes (Zanello et al, 2006). The electroactivity of carbon nanotube films makes these materials advantageous for tissue engineering applications involving electrically excitable tissues, such as muscles and nerves.…”

Chromatography of carbon nanotubes separated albumin from other serum proteins: a method for direct analysis of their interactions

“…In other words, there arises an urgent need for a good knowledge on the interaction between intact (chemically unmodified) MWCNT and proteins, especially cell-surface proteins [1][2][3] . In this paper, the classical column chromatography methodwhich entailed the use of a MWCNT-packed columnproved to be useful for the separation of serum proteins.…”

“…However, which protein(s) is(are) responsible for this strong adhesion remains an unresolved question 1,2) . To compound the intrigue surrounding the interaction between CNT and proteins, there remains a lack of a definitive tool and approach to investigate the interaction mechanism.…”