This approach yielded similar nanostructures prior to the transfer, made of thinner vertically aligned walls that collapsed onto the substrate during the transfer process (Figs. cellular calcium production), a later stage of bone cell differentiation, was Tonapofylline stimulated by the presence of the vertical CNWs on the surfaces. These results show that the graphene coatings, grown using the presented method, are biocompatible. And their topographies have an impact on cell behavior, which can be useful in tissue engineering applications. Electronic supplementary material The online version of this article (10.1007/s40820-018-0198-0) contains supplementary material, which is available to authorized users. test. Results and Discussion Surface Morphology of Graphene Surfaces The results of FE-SEM analysis of the surface morphology of the CNW and HGL films that were produced and transferred to the coverslips are presented in Fig.?1a, b, respectively. The CNW films consisted of thin graphene-like walls (up to 10?nm thick) that were perpendicular to the substrate in a spaced array of 2-m intervals on average (Fig.?1a). This type of graphene morphology represents a plasma-unique assembly of three-dimensional graphene, creating a scaffold that offers binding support for cells and an open-surface arrangement for molecular exchange. It possesses graphene structures at a similar order of magnitude to that of the organelles present on the cell surface and is also capable of accommodating smaller cells in between its walls. Furthermore, the process of formation and functionalization of these CNWs has been well studied, and the control of features widens their application capabilities [39, 44]. Open in a separate window Fig.?1 SEM images of the graphene-like samples. a CNW, b HGL nanostructures Tonapofylline on Thermanox? coverslips. These images show the clearly visible edges of the CNWs and the edges of the horizontally aligned CNWs The HGL surfaces were created using the same process as used for the CNWs, to maintain the chemical composition; however, a lower relative concentration of methane was used. This approach yielded similar nanostructures prior to the transfer, made of thinner vertically aligned walls that collapsed onto the substrate during the transfer process (Figs. S1 and S2), leaving the few-layered graphene sheets (10?nm thick, 1?m2 of area) lying horizontally on the substrate surface (Fig.?1b). However, these horizontal graphene sheets do not collapse in a uniform and completely flat manner, as can be seen in Fig.?1b where Flt3 some of the sheets have edges raised from the surface that appear brighter in the image (owing to charging effects) and show some of the sheet boundaries. Nanostructures presenting a similar thickness and crystalline structure have been produced by the same process and extensively characterized by van der Laan and by Pineda et al. [36C38, 40, 45C47]. It should be noted that techniques have been developed to produce horizontally oriented CNWs by blinding the electromagnetic field of the plasma process, which follows a different growth mechanism [39]. These horizontally aligned, texturized surfaces were used to compare with the CNW surfaces, as they provided Tonapofylline both a reduced graphene surface area (with only one plane available) and fewer topographical features for biological interactions while retaining the interactivity with the complex chemical system of the culture medium. These topographical differences were used to discriminate the influence of the mechanical anchoring of the cells from the purely chemical influence of the presence of graphene. Surface Composition of Graphene Surfaces Raman spectroscopy was used to evaluate the similarities between the surface compositions of the CNW and HGL films. The Raman signals (Fig.?2) verified the growth of the graphene-like films through the presence of the graphene-specific bands of disorder (D at 1350?cm?1), graphite (G at 1580?cm?1), and second-order disorders (G at 2690?cm?1). The D-band is related to the crystallite size effect and structural defects in the interaction between the aromatic moieties of the molecules and the graphene plane [21]. Similarly, other graphene-based topographical features (grids) presented highly accelerated differentiation that was also attributed to their ability to adsorb chemical inducers [23]. Furthermore, our results of a synergistic association of graphene and growth factors yielded higher differentiation, in accordance with previous reports [23]. Notably, the aforementioned effects for the HGL samples could be further enhanced on the CNW samples owing to their higher.
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