Iron(III)‐Selective Chelation‐Enhanced Fluorescence Sensing for In Vivo Imaging Applications

A “turn‐on” pattern Fe³⁺‐selective fluorescent sensor was synthesized and characterized that showed high fluorescence discrimination of Fe³⁺ over Fe²⁺ and other tested ions. With a 62‐fold fluorescence enhancement towards Fe³⁺, the probe was employed to detect Fe³⁺ in vivo in HeLa cells and Caenorhabditis elegans, and it was also successfully used to elucidate Fe³⁺ enrichment and exchange infected by innexin3 (Inx3) in hemichannel‐closed Sf9 cells.     

Fabrication of Fluoropolymer Microtubes via RAFT Copolymerization of N,N′‐Methylene Bisacrylamide Gel Fibers and Fluoromonomer

Fluoropolymer microtubes with a smooth surface were fabricated in more than 70 % yield via reversible addition fragmentation chain transfer (RAFT) co‐polymerization of N,N′‐methylene bisacrylamide (MBA) gel fibers as both template and monomer, 2‐(perfluoro‐3‐methylbutyl)ethyl acrylate (R‐3420) as co‐monomer, and pentaerythritol tetraacrylate (PET4A) as cross‐linker. The resulting fluoropolymer microtubes were characterized fully by SEM, TEM, EDS, XPS, and FT‐IR. The influence of the monomer composition on the yields and morphologies of the tubes were investigated in detail. The results indicated that polymer microtubes with a smooth surface were obtained at suitable amounts of R‐3420 and PET4A. Because of the decreased solubility of MBA gel fibers, the wall thickness increased as more R‐3420 was used. In the presence of PET4A, the solution polymerization could be facilitated and more R‐3420 could be attached onto the tubes based on FT‐IR analysis. The water contact angle and swelling ratio measurements both revealed the low hydrophilicity and high lipophilicity of the fluoropolymer microtubes, which made the sample able to absorb toluene selectively in a water/toluene two‐phase system.     

Ferrocenylethynyl‐Terminated Azobenzenes: Synthesis,Electrochemical, and Photoisomerization Studies

Ferrocenylethynyl‐terminated derivatives 8 – 12 have been synthesized and characterized by electrochemistry and UV/Vis spectroscopy. The electrochemical and photophysical studies indicate that the electronic communication in ferrocenylethynyl‐substituted derivatives is strongly influenced by the substituted position of the ferrocenylethynyl moiety. In situ electrochemical oxidation or chemical oxidation caused a characteristically weak ligand‐to‐metal charge‐transfer (LMCT) band to appear at 700–1000 nm. Subsequent electrochemical reduction or chemical reduction recovered the most of the original curve and the color of the solution as well. Among the derivatives, compound 8 exhibits the highest cis/trans molar ratio (64:36) in the photostationary state (PSS) upon light irradiation at 365 nm. Compound 8 exhibits excellent fatigue resistance and reversibility under several repeated reversible isomerization cycles.     

Pt nanohelices with highly ordered horizontal pore channels as enhanced photothermal materials

Recent studies have further demonstrated that the conjugation of noble metal helical nanostructures could alter their optical and catalytic activities. However, the intrinsic isotropic crystal growth of Pt makes the synthesis of high-quality Pt NCs with unique porous or branched nanostructures difficult. In this work, a new, powerful capping agent, N,N-dimethyloctadecylammonium bromide acetate sodium, was synthesized and used to coordinate Pt ions, slowing down the reaction rate. As a result, in aqueous solution, Pt nanohelices with highly ordered horizontal pore channels were successfully fabricated. Importantly, the Pt nanohelices were composed of several sub-2 nm Pt nanowires coiled together around a central point. The as-obtained samples exhibited enhanced photothermal properties compared with the classic Pt nanoparticles.     

Monodispersed AuPd nanoalloy: composition control synthesis and catalytic properties in the oxidative dehydrogenative coupling of aniline

A series of AuPd@C nanoalloy catalysts with tunable compositions were successfully prepared by a co-reduction method. The use of borane-tert-butylamine complex as reductant and oleylamine as both solvent and reductant was very effective for the preparation of the monodispersed nanoalloy. We evaluated the catalytic activity of these AuPd@C nanoalloys for oxidative dehydrogenative coupling of aniline, which showed better catalytic activity than equal amounts of sole Au@C or Pd@C catalyst. The Au₁Pd₃@C catalyst exhibited the best performance, indicating that the conversion and selectivity were improved along with the increase of Pd composition. However if the Pd composition was too high in the AuPd alloy, Au₁Pd₇@C achieved only 81% conversion in this reaction.     

Dual-peptide-modified alginate hydrogels for the promotion of angiogenesis

The ability to supply suitable blood vessel system is a major challenge for artificial thick tissue engineering. Angiogenesis is a key point during the process of microvascular formation. Many bioactive molecules such as extra cellular matrix(ECM) proteins and adhesion peptides derived from the ECM are applied to promote angiogenesis. In this work, two adhesion peptides, YIGSR and REDV, were selected to modify sodium alginate(ALG) to obtain YIGSR- and REDV-alginate conjugates(ALG-YIGSR, and ALG-REDV, respectively). We mixed the two peptide-conjugates together in a series of concentration ratios to prepare bioactive surfaces for in vitro studies and hydrogel scaffolds for in vivo studies. In vitro studies showed that surfaces modified with 1.09 pmol/mm2 peptide had the best affinity to human umbilical vein endothelial cells(HUVECs) than that with high or low concentrations of peptides. In addition, surfaces modified with dual peptides could significantly promote HUVECs proliferation, where ALG-YIGSR:ALG-REDV at a mole ratio of 5:1 exhibited the best enhancement ability. Furthermore, the in vivo angiogenesis results demonstrated that hydrogel scaffolds composed of mixed ALG-YIGSR and ALG-REDV at the 5:1 ratio had angiogenic induction potential by stimulating new blood vessel formation, and showed higher blood vessel density than scaffolds composed of a single peptide. These results demonstrated that a mixed combination of peptide alginate conjugates could be a potential scaffold to stimulate and induce angiogenesis in tissue engineering applications.     

Synthesis of open-mouthed,yolk–shell Au@AgPd nanoparticles with access to interior surfaces for enhanced electrocatalysis

We have successfully produced open-mouthed, yolk–shell (OM-YS) Au@AgPd nanoparticles (NPs) via galvanic replacement reaction at room temperature; each NP has a large opening on its AgPd shells. Owing to the openings on the AgPd shells, the inner surfaces of the AgPd shells of as-prepared OM-YS Au@AgPd NPs become accessible to the surrounding media. These new structural characters make the present OM-YS Au@AgPd NPs excellent catalysts for electrochemical oxidation of ethanol in alkaline media. Their electrochemical active surface area is 87.8 m² g^–1 and the mass activity is 1.25 A mg_Pd^–1. Moreover, the openings on the AgPd shells also make the surfaces of the Au cores in OM-YS Au@AgPd NPs accessible to the reaction media, which significantly facilitates the removal of CO and other carbonaceous intermediate species, thus leading to substantially enhanced durability and stability. This superior electrocatalytic performance cannot be implemented by using conventional YS Au@AgPd NPs or commercially available Pd/C catalysts.