Understanding the intermolecular interaction potential, V(r), of proteins under the influence of temperature, pressure, and salt concentration is essential for understanding protein aggregation, crystallization, and protein phase behavior in general. Here, we report small-angle x-ray scattering studies on dense lysozyme solutions of high ionic strength as a function of temperature and pressure. We show that the interaction potential changes in a nonlinear fashion over a wide range of temperatures, salt, and protein concentrations. Neither temperature nor protein and salt concentration lead to marked changes in the pressure dependence of V(r), indicating that changes of the water structure dominate the pressure dependence of the intermolecular forces. Furthermore, by analysis of the temperature, pressure, and ionic strength dependence of the normalized second virial coefficient, b2, we show that the interaction can be fine-tuned by pressure, which can be used to optimize b2 values for controlled protein crystallization.

Hydrogen produced via water electrolysis powered by renewable electricity or green H2 offers new decarbonization pathways. Proton exchange membrane water electrolysis (PEMWE) is a promising technology although the current density, temperature, and H2 pressure of the PEMWE will have to be increased substantially to curtail the cost of green H2. Here, a porous transport layer for PEMWE is reported, that enables operation at up to 6 A cm−2, 90 °C, and 90 bar H2 output pressure. It consists of a Ti porous sintered layer (PSL) on a low‐cost Ti mesh (PSL/mesh‐PTL) by diffusion bonding. This novel approach does not require a flow field in the bipolar plate. When using the mesh‐PTL without PSL, the cell potential increases significantly due to mass transport losses reaching ca. 2.5 V at 2 A cm−2 and 90 °C. On the other hand, the PEMWE with the PSL/mesh‐PTL has the same cell potential but at 6 A cm−2, thus increasing substantially the operation range of the electrolyzer. Extensive physical characterization and pore network simulation demonstrate that the PSL/mesh‐PTL leads to efficient gas/water management in the PEMWE. Finally, the PSL/mesh‐PTL is validated in an industrial size PEMWE in a container operating at 90 bar H2 output pressure.

The heat-induced desorption and adsorption of the proteins lysozyme, ribonuclease A, bovine serum albumin, and fibronectin at protein layers was investigated in two different environments: pure buffer and protein solution. Using two different environments allows us to distinguish between thermodynamic and kinetic mechanisms in the adsorption process. We observed a desorption in buffer and an adsorption in protein solution, depending upon protein properties, such as size, stability, and charge. We conclude that the desorption in buffer is mainly influenced by the mobility of the proteins at the interface, while the adsorption in protein solution is driven by conformational changes and, thereby, a gain in entropy. These results are relevant for controlling biofilm formation at solid-liquid interfaces.

A high-pressure cell for in situ X-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for the in situ investigation of adsorption phenomena in biological systems.

PEM Electrolysis In article number 2100630, Aldo Sau Gago and co‐workers develop novel porous transport layers for proton exchange membrane water electrolyzers, allowing operation under extreme conditions of current density, temperature, and pressure. By optimizing the water/gas transport properties of this component, a flow field in the bipolar plate becomes unnecessary. Thus, high production rates of hydrogen can be achieved efficiently, making it more economically attractive.