Using molecular dynamics simulation, we show direct evidence of the unexpected phenomenon of "water that does not wet a water monolayer" at room temperature. This phenomenon is attributed to the structure of the water beneath the water droplet, which exhibits an ordered water monolayer. Remarkably, there remains a considerable number of dangling OH bonds in this room temperature water monolayer, in contrast with the absence of dangling OH bonds at cryogenic temperature.

The interaction between nanomaterial and biomolecules is essential to nanoparticle-based biotechnology and biomedical applications, such as gene delivery, 1 cellular imaging, 2 tumor therapy, 3 and biological experimental technology. 4 It is also critical for the understanding of the growing concerns about the biosafety of these nanomaterials. 5À11 There have been extensive studies recently on the adsorption of proteins onto nanomaterial, particularly graphitic nanomaterials such as carbon nanotubes and fullerenes, both experimentally and theoretically, and it is shown that these adsorptions can affect both protein structures and functions. For example, Wu and co-workers have found that there are local structural distortions after protein streptavidin is bound onto a single-wall carbon nanotube (SWCNT). 12 Karajanagi et al. have also observed changes in both conformation and activity of two enzymes, α-chymotrypsin and soybean peroxidase, upon adsorption onto SWCNTs. 13 We have recently found that SWCNTs can plug into the hydrophobic cores of signaling and pathway regulatory proteins, WW domains, to form stable complexes 14 and can also win the competitive binding over the native binding ligand (proline-rich motifs) on the SH3 domain, 15 which are two possible routes of nanoparticles affecting protein functions.ProteinÀgraphene interactions, on the other hand, are relatively less studied. Graphene is a flat monolayer of carbon atoms