Fluorine-Doped SnO₂@Graphene Porous Composite for High Capacity Lithium-Ion Batteries

For the first time, a composite of fluorine-doped SnO₂ and reduced graphene oxide (F-SnO₂@RGO) was synthesized using a cheap F-containing Sn source, Sn­(BF₄)₂, through a hydrothermal process. X-ray photoelectron spectroscopy and X-ray diffraction results identified that F was doped in the unit cells of the SnO₂ nanocrystals, instead of only on the surfaces of the nanoparticles. F doping of SnO₂ led to more uniform and higher loading of the F-SnO₂ nanoparticles on the surfaces of RGO sheets, as well as enhanced electron transportation and Li ion diffusion in the composite. As a result, the F-SnO₂@RGO composite exhibited a remarkably high specific capacity (1277 mA h g^–1 after 100 cycles), a long-term cycling stability, and excellent high-rate capacity at large charge/discharge current densities as anode material for lithium ion batteries. The outstanding performance of the F-SnO₂@RGO composite electrode could be ascribed to the combined features of the composite electrode that dealt with both the electrode dynamics (enhanced electron transportation and Li ion diffusion due to F doping) and the electrode structure (uniform decoration of the F-SnO₂ nanoparticles on the surfaces of RGO sheets and the three-dimensional porous structures of the F-SnO₂@RGO composite)

Nonionic Block Copolymers Assemble on the Surface of Protein Bionanoparticle

Efficient delivery of therapeutic proteins to a target site remains a challenge due to rapid clearance from the body. Here, we selected tobacco mosaic virus (TMV) as a model protein system to investigate the interactions between the protein and a nonionic block copolymer as a possible protecting agent for the protein. By varying the temperature, we were able to obtain core–shell structures based on hydrophobic interactions among PO blocks and noncovalent interactions between TMV and EO blocks. The protein–polymer interactions were characterized by dynamic light scattering and isothermal titration calorimetry. This study establishes principles for the possible design of clinically useful protein delivery systems

High Performance Nanocrystals of a Donor–Acceptor Conjugated Polymer

Highly crystalline, well-defined nanowires of a donor–acceptor (D–A) conjugated polymer based on bithiazole-thiazolothiazole (PTz) were successfully prepared by a facile solution self-assembly method. In PTz nanowires, polymer chains align along the long axis of the nanowires forming lamellar structures with close π-stacking perpendicular to the long axis of the nanowires. The nanowires possess a single crystal structure with orthorhombic crystal unit cell in which the lattice parameters are <i>a</i> ≈ 21.05 Å, <i>b</i> ≈ 6.94 Å, and <i>c</i> ≈ 4.64 Å. The intrinsic charge transport property of PTz was characterized by using its single crystal nanowires in field-effect transistors with a mobility up to 0.46 cm² V^–1 s^–1. As an example of PTz single crystal nanowires in optoelectronic application, phototransistors of PTz nanowires exhibited a photoresponsivity up to 2531 A W^–1 and a photosensitivity up to 1.7 × 10⁴

Tobacco Mosaic Virus-Based 1D Nanorod-Drug Carrier via the Integrin-Mediated Endocytosis Pathway

For cancer therapy, viruses have been utilized as excellent delivery vehicles because of their facile transfection efficiency in their host cells. However, their inherent immunogenicity has become the major obstacle for their translation into approved pharmaceuticals. Herein, we utilized rodlike plant virus, tobacco mosaic virus (TMV), which is nontoxic to mammals and mainly infects tobacco species, as anticancer nanorod-drug vector for cancer therapy study. Doxorubicin (DOX) was installed in the inner cavity of TMV by hydrazone bond, which enabled the pH-sensitive drug release property. Conjugation of cyclic Arg-Gly-Asp (cRGD) on the surface of TMV can enhance HeLa cell uptake of the carrier via the integrin-mediated endocytosis pathway. Comparing with free DOX, the cRGD-TMV-hydra-DOX vector had similar cell growth inhibition and much higher apoptosis efficiency on HeLa cells. Moreover, the in vivo assay assumed that cRGD-TMV-hydra-DOX behaved similar antitumor efficiency but much lower side effect on HeLa bearing Balb/c-nu mice. Our work provides novel insights into potentially cancer therapy based on rodlike plant viral nanocarriers

Graphene Oxide: A Versatile Agent for Polyimide Foams with Improved Foaming Capability and Enhanced Flexibility

Close-celled aromatic polyimide (PI)/graphene foams with low density and improved flexibility were fabricated by thermal foaming of poly­(amic ester)/graphene oxide (PAE/GO) precursor powders. The PAE/GO precursor powders were prepared by grafting GO nanosheets with PAE chains, which led to efficient dispersion of the GO nanosheets in PAE matrix. Incorporation of GO resulted in an enhanced foaming capability of the precursor, i.e., enlarged cell size and decreased foam density. Notably, a decrease of 50% in the foam density was obtained via the addition of only 2 wt % GO in the precursor. In the foaming process, the GO nanosheets functioned as a versatile agent that not only provided heterogeneous nucleation sites but also produced gaseous molecules. By analyzing the foaming mechanism, the excellent features of GO in heat transfer, gas barrier, and strength reinforcement also facilitated to obtain large and uniform cells in the foams. In addition, the PI/graphene foams exhibited a prominent flexibility and enhanced flexural strength, as an elastic-to-nonelastic conversion of the initial stage of the compressive stress–strain curves was observed by increasing the content of graphene in the PI matrix and an increase of 22.5% in flexural strength was obtained by addition of 0.5 wt % GO in the precursor