laboratoire de physique statistique
 
 
laboratoire de physique statistique

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P U B L I C A T I O N S



 
2016
Chemisorption of Hydroxide on 2D Materials from DFT Calculations: Graphene versus Hexagonal Boron Nitride - Grosjean, Benoit and Pean, Clarisse and Siria, Alessandro and Bocquet, Lyderic and Vuilleumier, Rodolphe and Bocquet, Marie-Laure
JOURNAL OF PHYSICAL CHEMISTRY LETTERS 74695-4700 (2016)

Abstract : Recent nanofluidic experiments revealed strongly different surface charge measurements for boron-nitride (BN) and graphitic nanotubes when in contact with saline and alkaline water (Nature 2013, 494, 455-458; Phys. Rev. Lett. 2016, 116, 154501). These observations contrast with the similar reactivity of a graphene layer and its BN counterpart, using density functional theory (DFT) framework, for intact and dissociative adsorption of gaseous water molecules. Here we investigate, by DFT in implicit water, single and multiple adsorption of anionic hydroxide on single layers. A differential adsorption strength is found in vacuum for the first ionic adsorption on the two materials-chemisorbed on BN while physisorbed on graphene. The effect of implicit solvation reduces all adsorption values, resulting in a favorable (nonfavorable) adsorption on BN (graphene). We also calculate a pK(a) similar or equal to 6 for BN in water, in good agreement with experiments. Comparatively, the unfavorable results for graphene in water echo the weaker surface charge measurements but point to an alternative scenario.
 
2009
Single-molecule Visualization of Binding Modes of Helicase to DNA on PEGylated Surfaces - Yokota, Hiroaki and Han, Yong-Woon and Allemand, Jean-Francois and Xi, Xu Guang and Bensimon, David and Croquette, Vincent and Ito, Yoshihiro and Harada, Yoshie
CHEMISTRY LETTERS 38308-309 (2009)

Abstract : Binding modes of helicase to various DNA substrates were visualized by single-molecule fluorescence imaging on silicate coverslips coated with poly(ethylene glycol) (PEG) which minimizes the background noise from nonspecific protein adsorption. The results clearly show that the helicase has higher affinity for double-stranded DNA (dsDNA) with a single-stranded DNA (ssDNA) tail than that without one and that multiple helicases can bind to 4.7-kilonucleotide (knt) ssDNA. The study reported here will enhance the capabilities of single-molecule fluorescence studies on DNA-protein interactions.