Ultrastrong and Deformable Aluminum-Based Composite Nanolaminates with Transformable Binary Intergranular Films.

Nanostructured metals with conventional grain boundaries or interfaces exhibit high strength yet usually poor ductility. Here we report an interface engineering strategy that breaks the strength-ductility dilemma via externally incorporating graphene oxide at lamella boundaries of aluminum (Al) nanolaminates. By forming the binary intergranular films where graphene oxide was sandwiched between two amorphous alumina layers, the Al-based composite nanolaminates achieved ultrahigh compressive strength (over 1 GPa) while retaining excellent plastic deformability. Complementing experimental results with molecular dynamics simulation efforts, the ultrahigh strength was interpreted by the strong blocking effect of the binary intergranular films on dislocation nucleation and propagation, and the excellent plasticity was found to originate from the stress/strain-induced crystalline-to-amorphous transition of graphene oxide and the synergistic deformation between Al nanolamellas and the binary intergranular films.

Realizing reversible phase transformation of shape memory ceramics constrained in aluminum.

Small-scale shape memory ceramics exhibit superior shape memory or superelasticity properties, while their integration into a matrix material and the subsequent attainment of their reversible tetragonal-monoclinic phase transformations remains a challenge. Here, cerium-doped zirconia (CZ) reinforced aluminum (Al) matrix composite is fabricated, and both macroscopic and microscopic mechanical tests reveal more than doubled compressive strength and energy absorbance of the composites as compared with pure Al. Full austenitization in the CZ single-crystal clusters is achieved when they are constrained by the Al matrix, and reversible martensitic transformation triggered by thermal or stress stimuli is observed in the composite micro-pillars without causing fracture in the composite. These results are interpreted by the strong geometric confinement offered by the Al matrix, the robust CZ/Al interface and the local three-dimensional particle network/force-chain configuration that effectively transfer mechanical loads, and the decent flowability of the matrix that accommodates the volume change during phase transformation.

Principles of Inter-Amino-Acid Recognition Revealed by Binding Energies between Homogeneous Oligopeptides.

We have determined the interaction strengths of the common naturally occurring amino acids using a complete binding affinity matrix of 20 × 20 pairs of homo-octapeptides consisting of the 20 common amino acids between stationary and mobile states. We used a bead-based fluorescence assay for these measurements. The results provide a basis for analyzing specificity, polymorphisms, and selectivity of inter-amino-acid interactions. Comparative analyses of the binding energies, i.e., the free energies of association (ΔG A), reveal contributions assignable to both main-chain-related and side-chain-related interactions originating from the chemical structures of these 20 common amino acids. Side-chain-side-chain and side-chain-main-chain interactions are found to be pronounced in an identified set of amino acid pairs that determine the basis of inter-amino-acid recognition.

The highly efficient photocatalytic and light harvesting property of Ag-TiO2 with negative nano-holes structure inspired from cicada wings.

The negative replica of biomorphic TiO2 with nano-holes structure has been effectively fabricated directly from nano-nipple arrays structure of cicada wings by using a simple, low-cost and highly effective sol-gel ultrasonic method. The nano-holes array structure was well maintained after calcination in air at 500 °C. The Ag nanoparticles (10 nm-25 nm) were homogeneously decorated on the surface and to the side wall of nano-holes structure. It was observed that the biomorphic Ag-TiO2 showed remarkable photocatalytic activity by degradation of methyl blue (MB) under UV-vis light irradiation. The biomorphic Ag-TiO2 with nano-holes structure showed superior photocatalytic activity compared to the biomorphic TiO2 and commercial Degussa P25. This high-performance photocatalytic activity of the biomorphic Ag-TiO2 may be attributed to the nano-holes structure, localized surface plasmon resonance (LSPR) property of the Ag nanoparticles, and enhanced electron-hole separation. Moreover, the biomorphic Ag-TiO2 showed more absorption capability in the visible wavelength range. This work provides a new insight to design such a structure which may lead to a range of novel applications.

Peptide-Functionalized Nanomaterials for the Efficient Isolation of HER2-Positive Circulating Tumor Cells.

The detection of circulating tumor cells (CTCs) with a specific antigen expression is necessary in therapeutic response monitoring and targeted therapy guidance. The existence of human epidermal growth factor receptor 2 (HER2) and the concentration of HER2-positive CTCs are strong indicators for patient diagnosis, prognosis, and therapeutic monitoring. Herein we report the direct isolation of HER2-positive CTCs by peptide-functionalized nanomaterials. We designed and screened out a peptide as an HER2 antibody alternative demonstrating high HER2 affinity and selectivity. This HER2 recognition peptide bound efficiently with HER2 at the ligand-binding domain. Efficient HER2-positive CTC capture and detection were demonstrated using magnetic nanoparticles functionalized with the HER2 recognition peptide.