Fig. 2
From: Uptake of label-free graphene oxide by Caco-2 cells is dependent on the cell differentiation status
Interaction of GO and GNP with the cell surface of undifferentiated Caco-2 cells. SEM images of undifferentiated Caco-2 cells exposed to either 40 µg/ml GO1 (A, B), GO3 (C, D) or GNP (E, F) for 24 h. B Is displayed in false-coloration to enhance visibility of GO1 (purple) in contrast to the cell surface (grey). GO3 sheets (C, D) exhibit several folds and show agglomeration forming larger mats of GO on the cell surface. Hints are given towards a simultaneous uptake of several GO3 sheets in form of larger agglomerates. For further SEM images see Additional file 1: Figures S3 and S4