A Universal and Ultrastable Mineralization Coating Bioinspired from Biofilms

A simple and universal method for manufacturing a mineralization coating on various surfaces is developed using a biofilm‐based material obtained from engineered curli nanofibers. The amyloid protein (CsgA) is the main proteinaceous component in the Escherichia coli (E. coli) biofilm, which can withstand detergents in the harsh environment. The peptide sequence DDDEEK is bioinspired from salivary acquired pellicles in the dental plaque biofilm, having a strong ability to absorb mineral ions and induce the formation of biominerals. The bioinspired coating is successfully secreted by the engineered E. coli, which is transformed with a recombinant plasmid for expression with T7 promoter (PET), namely PET‐22b‐CsgA‐DDDEEK plasmid. The uniform coating can bear shear force and stay on virtually any type of material surface for at least one month. Moreover, the coated slices had a good mineralization performance and better stability than hydroxyapatite (HA)‐spray slices. Furthermore, MG63 cells on the bioactive HA layer induced by the coating possess a better growth capacity than those on the commercial product Matrigel. The animal experiment results suggest that the coated Ti₆Al₄V screws with induced HA present better osteogenicity and osseointegration than HA‐sprayed screws after 12 weeks, as well as no extra immunogenicity. Thus, the coating is highly promising for biomedical applications.     

Three‐Dimensional Heteroatom‐Doped Carbon Nanofiber Networks Derived from Bacterial Cellulose for Supercapacitors

Recently, heteroatom‐doped three‐dimensional (3D) nanostructured carbon materials have attracted immense interest because of their great potential in various applications. Hence, it is highly desirable to exploit a simple, renewable, scalable, multifunctional, and general strategy to engineer 3D heteroatom‐doped carbon nanomaterials. Herein, a simple, eco‐friendly, general, and effective way to fabricate 3D heteroatom‐doped carbon nanofiber networks on a large scale is reported. Using this method, 3D P‐doped, N,P‐co‐doped, and B,P‐co‐doped carbon nanofiber networks are successfully fabricated by the pyrolysis of bacterial cellulose immersed in H₃PO₄, NH₄H₂PO₄, and H₃BO₃/H₃PO₄ aqueous solution, respectively. Moreover, the as‐prepared N,P‐co‐doped carbon nanofibers exhibit good supercapacitive performance.     

Synthesis of Microporous Carbon Nanofibers and Nanotubes from Conjugated Polymer Network and Evaluation in Electrochemical Capacitor

One‐dimensional fibers and tubes are constructed through the oriented carbon‐carbon cross‐linking reactions towards rigid conjugated polymer networks. As the result, a template‐free and one‐step synthesis of CNTs and CNFs is achieved through a simple carbonization of the as‐formed carbon‐rich tubular and fiberlike polyphenylene precursors under argon. Microporous CNTs and CNFs with a surface area up to 900 m² g^–1 are obtained, together with HR‐TEM characterizations indicating the formation of intrinsic microporous structure in these rigid carbon‐rich networks. The primary electrochemical experiments reveal their promising applications as advanced electrodes in electrochemical double‐layered capacitor (EDLC).     

High Pseudocapacitance from Ultrathin V2O5 Films Electrodeposited on Self‐Standing Carbon‐Nanofiber Paper

An ultrathin V₂O₅ layer was electrodeposited by cyclic voltammetry on a self‐standing carbon‐nanofiber paper, which was obtained by stabilization and heat‐treatment of an electrospun polyacrylonitrile (PAN)‐based nanofiber paper. A very‐high capacitance of 1308 F g^?1 was obtained in a 2 M KCl electrolyte when the contribution from the 3 nm thick vanadium oxide was considered alone, contributing to over 90% of the total capacitance (214 F g^?1) despite the low weight percentage of the V₂O₅ (15 wt%). The high capacitance of the V₂O₅ is attributed to the large external surface area of the carbon nanofibers and the maximum number of active sites for the redox reaction of the ultrathin V₂O₅ layer. This ultrathin layer is almost completely accessible to the electrolyte and thus results in maximum utilization of the oxide (i.e., minimization of dead volume). This hypothesis was experimentally evaluated by testing V₂O₅ layers of different thicknesses.