Interfacial reinforced carbon fiber composites inspired by biological interlocking structure.

Weak interfacial activity and poor wettability between fiber and matrix are known to be the two main factors that restrict the mechanical properties of carbon fiber-reinforced composites (CFRCs). Herein, inspired by high strength and toughness characteristics of wing feathers of Black Kite (Milvus migrans), natural hook-groove microstructure system (HGMS) and underlying mechanical interlocking mechanism were carefully investigated. Biomimetic HGMS based on dopamine-functionalized carbon fibers and ZnO nanorods were constructed successfully by a two-step modification method to enhance interfacial adhesion. Further, CFRCs featured with biomimetic HGMS were prepared by a vacuum-assisted contact molding method. Experimental results confirmed that flexural strength and interlaminar shear strength of the bioinspired CFRCs were effectively improved by 40.02 and 101.63%, respectively. The proposed bioinspired design strategy was proved to be flexible and effective and it was anticipated to provide a promising design approach and facile fabrication method for desirable CFRCs with excellent mechanical properties.

A novel heterometallic ruthenium-silver complex as potential antitumor agent: Studies on its synthesis, in vitro assays and interactions with biomolecular targets.

Certain ruthenium compounds are found to be potent growth inhibitors for cancer cells. In the current study, a novel ruthenium-triphenylphosphine (PPh3) cation and silver-2-mercapto nicotinate acid (H2mna) anion complex (RSC) was synthesized, and its molecular structure was determined by IR, NMR and X-ray crystallography. Biological assays revealed that RSC strongly inhibited the viability of MCF-7 and MDA-MB-231 cells with IC50 values of 9.6±1.1 and 7.5±0.8 µM, respectively, and significantly blocked their migration rates. Ultraviolet spectroscopy and fluorescence emission experiments demonstrated that RSC interacted with BSA, but not DNA. Further studies on [Ag6(Hmna)2(mna)4]4- binding with BSA and DNA found the anion did not interact with these biomolecules, indicating that RSC exerted its biological functions through its ruthenium-PPh3 complex (RTC) moiety, and molecular docking provided additional evidence supporting this result. Fluorescence resonance energy transfer showed that the number of binding sites (n) and binding constant of RTC-BSA complex were 1 and 8.60 × 104 M-1 at 310K, suggesting a strong interaction between RTC and BSA. The thermodynamic parameters ΔG0, ΔH0 and ΔS0 of the binding were calculated, and it was demonstrated that the binding of RTC with BSA was enthalpy-driven, and the main forces between RTC and BSA were electrostatic force and hydrogen bonding. Molecular docking showed that the binding site of BSA with RSC was located on the interface between the domains IIA and IIB of the protein. The present study sheds light on that a ruthenium mono-coordinated with PPh3 complex could help to design and develop a new class of antitumor drugs.

DNA-binding, photocleavage studies of ruthenium(II) complexes with 2-(2-quinolinyl) imidazo[4,5-f][1,10]phenanthroline.

Two new ruthenium complexes with [Ru(L)(2)(qip)](2+) (L=bpy (2,2'- bipyridine), phen (1,10-phenanthroline); qip=2-(2-quinolinyl)imidazo[4,5-f][1,10]phenanthroline), have been synthesized and characterized by elemental analysis, ES-MS, (1)H NMR. The binding properties of two complexes towards CT-DNA were investigated by various optical methods and viscosity measurements. The experiment results suggested that both Ru(II) complexes can intercalate into DNA base pairs. Strong quenching in emission intensity of two Ru(II) complexes were observed upon addition of Ag(+) in the absence and presence of CT-DNA. Furthermore, the two complexes can promote cleavage of pBR322 DNA under irradiation at 365 nm, and complex 2 exhibits a stronger DNA-photocleavage efficiency than complex 1. The mechanism of DNA cleavage suggests that singlet oxygen ((1)O(2)) is likely to be the cleaving agent.

DNA-binding and photocleavage studies of ruthenium(II) complexes containing asymmetric intercalative ligand.

A novel asymmetric ligand 2-(pyridine-2-yl)-1-H-imidazo[4,5-i]dibenzo[2,3-a:2',3'-c]phenazine (pidbp) and its ruthenium complexes [Ru(L)(2)(pidbp)](2+) (L=bpy (2, 2'- bipyridine), phen (1, 10 - phenanthroline)), have been synthesized and characterized by elemental analysis, ES-MS, (1)H NMR. Various methods support the conclusion that both Ru(II) complexes can intercalate into DNA base pairs. Complex [Ru(bpy)(2)(pidbp)](2+)4 exhibits its DNA "molecular light switch" properties. Furthermore, the two complexes are efficient DNA-photocleavers under irradiation at 365 nm, and complex 5 exhibits a stronger DNA-photocleavage efficiency than complex 4. The mechanism of DNA cleavage is an oxidative process by generating singlet oxygen.

Synthesis, DNA-binding and photocleavage of "light switch" complexes [Ru(bpy)2(pyip)]2+ and [Ru(phen)2(pyip)]2+.

Two novel Ru(II) complexes [Ru(bpy)(2)(pyip)](2+)1 and [Ru(phen)(2)(pyip)](2+)2 (bpy=2,2'-bipyridine; phen=1,10-phenanthroline; pyip=2-(pyridine-2-yl)imidazo-[4,5-f][1,10]-phenanthroline), have been synthesized and characterized by elemental analysis, ES-MS, (1)H NMR, UV-Vis. The DNA-binding behaviors of both complexes were studied by spectroscopic methods and viscosity measurements. The results indicate that the two complexes can bind to CT-DNA in an intercalative mode, and also show that these two Ru(II) complexes can promote the photocleavage of pBR322 DNA. In addition, In the presence of Co(2+), the emission of DNA-[Ru(L)(2)pyip](2+) can be quenched, which exhibited the DNA "light switch" properties.