Cobalt Polypyridyl-Based Electrolytes for p-Type Dye-Sensitized Solar Cells

Polypyridyl Co complexes with different substituents were applied as redox mediators in p-type dye-sensitized solar cells (p-DSCs), consisting of mesoporous NiO sensitized with a perylenemonoimide-naphthalenediimide (PMI-NDI) dyad. The photocurrent and photovoltages of the devices were found to depend on the steric bulk of the redox species rather than their electrochem. potential. Bulky substituents were found to slow the detrimental charge recombination reactions between holes in the NiO semiconductor and the reduced form of the redox couple. The open-circuit potential (VOC) of each of the devices was superior to the equiv. PMI-NDI-sensitized p-DSCs contg. the triiodide/iodide redox couple

Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer‐Induced Photoreduction in Phospholipid Bilayers

Photosystem I (PS I) is a transmembrane protein that assembles perpendicular to the membrane, and performs light harvesting, energy transfer, and electron transfer to a final, water-soluble electron acceptor. We present here a supramolecular model of it formed by a bicationic oligofluorene 1(2+) bound to the bisanionic photoredox catalyst eosin Y (EY2-) in phospholipid bilayers. According to confocal microscopy, molecular modeling, and time dependent density functional theory calculations, 1(2+) prefers to align perpendicularly to the lipid bilayer. In presence of EY2-, a strong complex is formed (K-a=2.1 +/- 0.1x10(6) m(-1)), which upon excitation of 1(2+) leads to efficient energy transfer to EY2-. Follow-up electron transfer from the excited state of EY2- to the water-soluble electron donor EDTA was shown via UV-Vis absorption spectroscopy. Overall, controlled self-assembly and photochemistry within the membrane provides an unprecedented yet simple synthetic functional mimic of PS I.Metals in Catalysis, Biomimetics & Inorganic Material

Design, structure and plasma binding of ancestral β-CoV scaffold antigens

We report the application of ancestral sequence reconstruction on coronavirus spike protein, resulting in stable and highly soluble ancestral scaffold antigens (AnSAs). The AnSAs interact with plasma of patients recovered from COVID-19 but do not bind to the human angiotensin-converting enzyme 2 (ACE2) receptor. Cryo-EM analysis of the AnSAs yield high resolution structures (2.6-2.8 angstrom) indicating a closed pre-fusion conformation in which all three receptor-binding domains (RBDs) are facing downwards. The structures reveal an intricate hydrogen-bonding network mediated by well-resolved loops, both within and across monomers, tethering the N-terminal domain and RBD together. We show that AnSA-5 can induce and boost a broad-spectrum immune response against the wild-type RBD as well as circulating variants of concern in an immune organoid model derived from tonsils. Finally, we highlight how AnSAs are potent scaffolds by replacing the ancestral RBD with the wild-type sequence, which restores ACE2 binding and increases the interaction with convalescent plasma. Development of vaccines remains challenging because viral antigens can be unstable or aggregate. Here, authors present ancestral sequence reconstruction as a method to generate stable and soluble antigens using exclusively available sequence information.</p