Flexible antibodies with nonprotein hinges

There is a significant need for antibodies that can bind targets with greater affinity. Here we describe a novel strategy employing chemical semisynthesis to produce symmetroadhesins: antibody-like molecules having nonprotein hinge regions that are more flexible and extendible and are capable of two-handed binding. Native chemical ligation was carried out under mild, non-denaturing conditions to join a ligand binding domain (Aβ peptide) to an IgG1 Fc dimer via discrete oxyethylene oligomers of various lengths. Two-handed Aβ–Fc fusion proteins were obtained in quantitative yield and shown by surface plasmon resonance to bind an anti-Aβ antibody with a KD at least two orders of magnitude greater than the cognate Aβ peptide. MALDI-TOF MS analysis confirmed the protein/nonprotein/protein structure of the two-handed molecules, demonstrating its power to characterize complex protein-nonprotein hybrids by virtue of desorption/ionization mediated by peptide sequences contained therein. We anticipate many applications for symmetroadhesins that combine the target specificity of antibodies with the novel physical, chemical and biological properties of nonprotein hinges

Enhanced Performance of Planar Perovskite Solar Cell by Graphene Quantum Dot Modification

In organic–inorganic halide perovskite solar cells (PSCs), the perovskite layer is the main source of photogenerated electron–hole pairs. Therefore, the premier concern in PSCs is to improve the quality of the perovskite film (PF). In the present research, graphene quantum dots (GQDs) were prepared and incorporated in the perovskite precursor, and due to the merits of dangling bonds, quantum size, and excellent electronic conductivity of GQDs, PF of higher-quality with flat surface and pinhole-free hallmarks was garnered. It is delightful that the PFs with GQDs exhibit higher light absorption and faster charge extraction. Consequently, the power conversion efficiency (PCE) of PSCs incorporating GQDs achieves an improvement of 11% compared with the pristine ones. Our work confirms that incorporating GQDs is a viable approach to obtain high-quality PF with more efficient charge extraction for superior planar PSCs

Hierarchical yolk-shell layered potassium niobate for tuned pH-dependent photocatalytic H2 evolution

Photocatalysts and the reaction environments in which they act are crucial for improving the photocatalytic efficiency. But the pH-dependent evolution of H2 photocatalysed using nanoscale potassium niobate particles with high surface areas has not received attention. In this study, a straightforward Ostwald ripening method was developed to synthesize KNb3O8 with a thin nanosheet assembled hierarchical yolk–shell structure and large surface area of 60.6 m2 g−1. The H2 evolution from a water–methanol solution in an alkaline to neutral environment was studied. The photocatalytic H2 evolution rates over fabricated hierarchical yolk–shell KNb3O8 increased when OH− concentrations were decreased. Such behaviour implied that the concentration of H+ dominated the H2 evolution over hierarchical yolk–shell KNb3O8 rather than the reduction ability from the conduction band, differing from the corresponding bulk material. This study demonstrated an efficient method to achieve a high H2 evolution rate in a neutral environment through the use of photocatalysts with hierarchical structures and large surface areas