Amyloid Fibers Increase Free Radicals of Synthetic Melanin.

Functional amyloid fibers are crucial in melanogenesis, but their roles are incompletely understood. In particular, their relationship with intrinsic spin characters of melanin remains unexplored. Here, we show that adding an amyloid scaffold greatly augments the spin density in synthetic melanin. It also brings about concurrent alterations in water dispersibility, bandgaps, and radical scavenging properties of the synthetic melanin, which facilitates its applications in solar water remediation and protection of human keratinocytes from UV irradiation. This work provides implications in the unrevealed role of functional amyloid in melanogenesis and in the origin of the superiority of natural melanin toward its synthetic variants in terms of the spin-related properties.

Biorenewable Polymer-Based Light-Absorbing Porous Hydrogel for Efficient Solar Steam Desalination.

An efficient interfacial heating system composed of a light-absorbing material and a hydrophilic porous support is developed through eco-friendly and energy-effective fabrication processes. Lignin nanoparticles (NPs) and cellulose nanofibers (CNFs) are harnessed as biorenewable light absorbers and hydrophilic supports, respectively. Lignin NPs are prepared using a solvent exchange process of the fractionated lignin with organic solvents to improve its π-π stacking and light-absorbing property for efficient photothermal conversion. Then, the lignin NPs are mixed with CNFs and lyophilized to obtain a light-absorbing porous hydrogel (LAPH), and the resulting LAPHs are covalently cross-linked and hybridized with Au NPs through a seed-mediated growth to further enhance their mechanical stability, hydrophilicity, and photothermal conversion properties. The resulting LAPHs exhibit an outstanding and prolonged performance as a solar steam generator such as high salt and pH tolerance, evaporation rate (3.17 kg m-2 h-1), and solar steam generation efficiency (83.4%) under 1 sun irradiation.