RESUMO
An effective method is presented for preparing high solid content azobenzene-containing triblock copolymer toroidal assemblies by liquid crystallization-assisted seeded dispersion polymerization. Vesicles are prepared via polymerization-induced self-assembly (PISA), and used as seeds for further chain extension. By introducing smectic liquid crystalline (LC) ordering into the core-forming block, toroids are formed in situ during the polymerization. The morphological transformation from toroids to barrels is observed under ultraviolet irradiation due to the photo-isomerization of the azobenzene mesogens. This strategy expands the scope of tunable anisotropic morphologies for potential functional nanomaterials based on a LC copolymer by seeded dispersion polymerization.
RESUMO
Electrochemical stimulus is a clean and simple choice of stimulating source in the field of stimuli-responsive materials. Herein, we report an electrochemically-responsive hybrid assembly of magnetic nanoparticles (Fe3O4@SiO2-PGMA-CD) and polyethylene glycol-Fc (PEG-Fc) based on the host-guest interaction between ß-cyclodextrin and ferrocene groups. Through electrochemical control, the hydrophilic polymer chains can be reversibly linked to or dropped off from the surface of the magnetic nanoparticles. Thus, the hydrophobic property of the surface together with the protein adsorption ability of the magnetic nanoparticles can be conveniently adjusted by voltages applied. A reversible protein adsorption/release transition from this novel hybrid material has been realized, demonstrated by the bovine serum albumin adsorption experiment. Therefore, an elegant material is introduced to achieve electrochemically-controlled reversible magnetic separation of proteins.
RESUMO
CO2-responsive polymer poly(N,N-diethylaminoethylmethacrylate)-modified magnetic nanoparticles (Fe3O4@dye/SiO2-PDEAEMA) were synthesized by atom transfer radical polymerization from the surfaces of silica coated, dye-labelled iron oxide nanoparticles (Fe3O4@dye/SiO2). TEM, FT-IR, and TGA confirmed and quantified the grafted polymer brushes. The prepared magnetic nanoparticles (MNPs) were fluorescence labelled, as shown by the fluorescence spectra and fluorescence microscopy images. This indicated that the nanoparticles could be utilized as imaging probes to monitor the movement of biological cells or other systems. The PDEAEMA polymer brushes on the surface of MNPs endowed them with a protein adsorption ability. The polymer was also CO2-responsive, so it was a CO2-triggered reversible protein adsorption/release material, which was demonstrated by the bovine serum albumin (BSA) adsorption experiments. The results indicated that the reversible adsorption/release of protein by bubbling CO2 and N2 alternately was easy to achieve.
RESUMO
BACKGROUND: The mechanisms of action for volatile anesthetics remain unknown for centuries partly owing to the insufficient or ineffective research models. We designed this study to develop three strains derived from a wild-type Drosophila melanogaster with different sensitivities to volatile anesthetics, which may ultimately facilitate molecular and genetic studies of the mechanism involved. METHODS: Median effective doses (ED(50)) of sevoflurane in seven-day-old virgin female and male wild-type Drosophila melanogaster were determined. The sensitive males and females of percentile 6 - 10 were cultured for breeding sensitive offspring (S(1)). So did median ones of percentile 48 - 52 for breeding median offspring (M(1)), resistant ones of percentile 91 - 95 for breeding resistant offspring (R(1)). Process was repeated through 31 generations, in the 37th generation, S(37), M(37) and R(37) were used to determine ED(50) for enflurane, isoflurane, sevoflurane, desflurane, halothane, methoxyflurane, chloroform and trichloroethylene, then ED(50) values were correlated with minimum alveolar concentration (MAC) values in human. RESULTS: From a wild-type Drosophila melanogaster we were able to breed three strains with high, median and low sevoflurane requirements. The ratio of sevoflurane requirements of three strains were 1.20:1.00:0.53 for females and 1.22:1.00:0.72 for males. Strains sensitive, median and resistant to sevoflurane were also sensitive, median and resistant to other volatile anesthetics. For eight anesthetics, ED(50) values in three strains correlated directly with MAC values in human. CONCLUSIONS: Three Drosophila melanogaster strains with high, median and low sensitivity to volatile anesthetics, but with same hereditary background were developed. The ED(50) are directly correlated with MAC in human for eight volatile anesthetics.
