Research on polypeptide multilayer films, coatings, and microcapsules is located at the intersection of several disciplines: synthetic polymer chemistry and physics, biomaterials science, and nanoscale engineering. The past few years have witnessed considerable growth in each of these areas. Unexplored territory has been found at the borders, and new possibilities for technology development are taking form from technological advances in polypeptide production, sequencing of the human genome, and the nature of peptides themselves. Most envisioned applications of polypeptide multilayers have a biomedical bent. Prospects seem no less positive, however, in fields ranging from food technology to environmental science. This review of the present state of polypeptide multilayer film research covers key points of polypeptides as materials, means of polymer production and film preparation, film characterization methods, focal points of current research in basic science, and the outlook for a few specific applications. In addition, it discusses how the study of polypeptide multilayer films could help to clarify the physical basis of assembly and stability of polyelectrolyte multilayers, and mention is made of similarities to protein folding studies.

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This work reports the first preparation and characterization of a hybrid PbS quantum dot (QD)/nanoporous NiO film nanostructure as well as its application for novel self-powered cathodic photoelectrochemical (PEC) sensing. Specifically, we synthesized the thioglycolic acid-capped PbS QDs and then assembled them onto the hydrothermally fabricated three-dimensional (3D) NiO nanostructured films on the transparent indium tin oxide-coated glass substrates, followed by the subsequent conjugation with the glucose oxidase as a model biocatalyst. Favorable alignment existed between the NiO and PbS QDs, and the as-obtained p-type heterostructure was characterized by various techniques and found to have good PEC activities. In the self-powered PEC biosensing of glucose, the system exhibited high sensitivity toward the presence of dissolved oxygen in the electrolyte, and thereby, a novel PEC enzymatic sensor was developed. With a PbS QD/3D NiO nanofilm, this work manifested the great promise of a heterostructure photocathode for a self-powered PEC biosensor that to the best of our knowledge has not been reported. We believe that it could inspire more interest in the design and development of numerous other p-type heterostructures for advanced self-powered PEC biosensors.

Summary The capability to maintain cell wall integrity is critical for plants to adapt to unfavourable conditions. l‐Arabinose (Ara) is a constituent of several cell wall polysaccharides and many cell wall‐localised glycoproteins, but so far the contribution of Ara metabolism to abiotic stress tolerance is still poorly understood. Here, we report that mutations in the MUR4 (also known as HSR8) gene, which is required for the biosynthesis of UDP‐Arap in Arabidopsis, led to reduced root elongation under high concentrations of NaCl, KCl, NaNO3, or KNO3. The short root phenotype of the mur4/hsr8 mutants under high salinity is rescued by exogenous Ara or gum arabic, a commercial product of arabinogalactan proteins (AGPs) from Acacia senegal. Mutation of the MUR4 gene led to abnormal cell−cell adhesion under salt stress. MUR4 forms either a homodimer or heterodimers with its isoforms. Analysis of the higher order mutants of MUR4 with its three paralogues, MURL, DUR, MEE25, reveals that the paralogues of MUR4 also contribute to the biosynthesis of UDP‐Ara and are critical for root elongation. Taken together, our work revealed the importance of the Ara metabolism in salt stress tolerance and also provides new insights into the enzymes involved in the UDP‐Ara biosynthesis in plants.