Hydrophobic hydration of poly-N-isopropyl acrylamide: a matter of the mean energetic state of water.

The enthalpically favoured hydration of hydrophobic entities, termed hydrophobic hydration, impacts the phase behaviour of numerous amphiphiles in water. Here, we show experimental evidence that hydrophobic hydration is strongly determined by the mean energetics of the aqueous medium. We investigate the aggregation and collapse of an amphiphilic polymer, poly-N-isopropyl acrylamide (PNiPAM), in aqueous solutions containing small amounts of alcohol and find that the thermodynamic characteristics defining the phase transitions of PNiPAM evolve relative to the solvent composition at which the excess mixing enthalpy of the water/alcohol mixtures becomes minimal.

Real-time observation of potential conformational changes of proteins during electromagnetic field exposure.

A novel experimental setup for the exposure of proteins to uniform electromagnetic fields in the frequency range from 50MHz up to 2GHz is presented. The exposure chamber can be placed in the measurement compartment of an existing spectropolarimeter recording the circular dichroism signal. Therefore, potential conformational changes induced by the electromagnetic fields can be observed.