A polymer and protein hybrid membrane can trap nanoparticles in aqueous solution and act as a solar absorber. Mady Elbahri and his team from the Institute of Material Science at Kiel University (KU) and the Institute of Polymer Research at Helmholtz-Zentrum Geesthacht (HZG), Germany, published details in the journal Advanced Functional Materials. They explain that conformational changes in the protein can sequester nanoparticles from solution but surprisingly the color of the nanoparticles shines through. Gold nanoparticles trapped are red when the material is dry but a perfect black absorber when wet. All in all, the result is a breakthrough towards the design of an operative filtration process, as a new route for the fabrication of functional materials, and offers commercially attractive efficiencies at a low cost, explains Elbahri.