Single-layer graphene modulates neuronal communication and augments membrane ion currents

The use of graphenebased materials to engineer sophisticated biosensing interfaces that can adapt to the central nervous system requires a detailed understanding of how such materials behave in a biological context. Graphene's peculiar properties can cause various cellular changes, but the underlying mechanisms remain unclear. Here, we show that singlelayer graphene increases neuronal firing by altering membraneassociated functions in cultured cells. Graphene tunes the distribution of extracellular ions at the interface with neurons, a key regulator of neuronal excitability. The resulting biophysical changes in the membrane include stronger potassium ion currents, with a shift in the fraction of neuronal firing phenotypes from adapting to tonically firing. By using experimental and theoretical approaches, we hypothesize that the graphene\u2013ion interactions that are maximized when singlelayer graphene is deposited on electrically insulating substrates are crucial to these effects

Tuning intermolecular interaction in long-range-ordered submonolayer organic films

The future success of organic electronic devices strongly depends on the ability to tailor the properties of thin films and interfaces. This calls for well-ordered thin films. However, their properties are dominantly influenced by the formation of the first molecular layer representing a template for further growth. The development of the first layer-in turn-depends on the fine balance of molecule-substrate and molecule-molecule interaction. The latter is usually attractive owing to van der Waals forces and causes the formation of islands and small crystalline grains. Here, we report on organic adsorbates exhibiting a repulsive intermolecular interaction. With increasing coverage, Sn-phthalocyanine molecules continuously rearrange on Ag(111) in a series of ordered superstructures. They always fill the surface terraces homogeneously and maximize the domain size. Thicker films also exhibit extremely large, monocrystalline grains and potentially enable bulk-like properties for thin films. The intermolecular interaction can be tuned by cooling and becomes attractive below similar to 120 K