Subnanoscale Hydrophobic Modulation of Salt Bridges in Aqueous Media.


Shuo Chen, Yoshimitsu Itoh, Takuya Masuda, Seishi Shimizu, Jun Zhao, Jing Ma, Shugo Nakamura, Kou Okuro, Hidenori Noguchi, Kohei Uosaki, and Takuzo Aida


Science 2015, 348, 555–559.

[DOI: 10.1126/science.aaa7532]

E-Field responsive functional Self-assembled monolayerS
  We have developed a novel stimuli responsive self-assembled monolayer, which could catch and release the surface-bound guest molecules in response to applied electrical potential.  During the course of the research, we have also found that a salt-bridge interaction between the guest and the monolayer is enhanced when approaching a hydrophobic surface in subnanoscale.
  On a protein surface, ion-pairs often exist near hydrophobic surfaces.  In the 1950s, these ion-pairs are predicted to be strongly bound together more than that in solution.  Our experimental observation of hydrophobic modulation of salt-bridge became the first experimental proof for this long-standing theory.