Wallace and Sansom, on the other hand, used steered coarse-grained molecular dynamics to investigate bilayer penetration by a hydrophobic NT. They simulated NTs with diameters from 1.4 to 6.1 nm and lengths of 5 and 10 nm. Their simulation results are in broad agreement with a recent experimental study, in which the force required to push large-diameter NTs into a living cell is measured using atomic force microscopy. As expected, the force required to penetrate the bilayer is shown to monotonically increase with an increase in NT diameter. Moreover, they found that there is no apparent effect on bilayer integrity following NT penetration.