Yu-Feng He

Study on effective extraction of chicken feather keratins and their films for controlling drug release

We report the fabrication of keratin films with porosity using keratin, for controlled drug delivery systems. Feathers are currently an important waste product from the poultry industry, however abandoned down products cause an environmentally difficult disposal problem as they are not efficiently extracted and applied. In this paper, feather keratin was extracted using a high-efficiency method. The yield of pure keratin was up to 90%. Its molecular weight was 20 kDa with low dispersity. The films, based on the extracted keratin, were prepared using a simple method, and showed good mechanical properties. Furthermore, the feather keratin films were used to load and release drugs. The resultant feather keratin biopolymer films were pH-responsive and showed controllable drug-release behavior. In summary, we achieved a simple method to reutilize disused feathers. It could be an attractive candidate for applications in the biomedical field.

Preparation and catalysis of porous silica supported metal Schiff-base complex

A series of porous silica support metal Schiff-base complexes was synthesized with amino porous silica, salicylaldehyde and metal ion, which characterized by IR spectra, elemental analysis, and SEM. The catalytic property for oxidation of olefins in the presence of molecular oxygen has been investigated. The major product of the aerobic oxidation without reductant was the epoxy. The influence of reaction temperature and additive for epoxidation had been studied. The selectivity and the conversion of epoxidation varied with reaction time, different additives and different catalysts.

Polymer-bound schiff-base complex catalyst for effective oxidation of olefins with molecular oxygen

Polymer-bound Schiff-base ligand (PS–SalPhe) was prepared from polystyrene-bound salicylaldehyde and phenylalanine, and its complex (PS–SalPhe–M) (M = Co, Mn) was also synthesized. The polymer ligand and its complex were characterized by infrared spectra, small area X-ray photoelectron spectroscopy, and ICP–AES. In the presence of the complex, cyclohexene can be effectively oxidized by molecular oxygen without a reductant. The major products of the reaction are 2-cyclohexen-1-ol (—OH), 2-cyclohexen-1-one (CO), and 2-cyclohexen-1-hydroperoxide (—OOH ), which is different from the typical oxidation of cyclohexene. The mechanism of cyclohexene oxidation is also discussed. Long-chain linear aliphatic olefins, such as 1-octene, 1-decene, 1-dodecene, and 1-tetradecene, can be directly oxidized by molecular oxygen catalyzed by PS–SalPhe–M (M = Mn, Co), which yields the 1,2-epoxy alkane.

Preparation of low-molecular-weight chitosan derivative zinc complexes and their effect on the growth of liver cancer cells in vitro

Low-molecular-weight (LMW) chitosan salicylaldehyde Schiff-base and its zinc(II) complexes were synthesized and characterized by Fourier transform-infrared (FT-IR) spectra, transmission electron microscopy (TEM), dynamic light scattering (DLS), gel permeation chromatography-multiangle laser light scattering (GPC-MALLS), and elemental analysis. The results of electrophoretic analysis suggest that the Zn complexes bound to DNA by means of electrostatic interactions and intercalation. The effect of the Zn complexes on the growth of SMMC-7721 liver cancer cells was investigated by sulforhodamine B assay in vitro. The results reveal that the growth of liver cancer cells was inhibited by LMW-chitosan and their Zn complexes. The inhibition rate of the Zn complexes was higher than that of LMW-chitosan ligand. The LMW-chitosan Schiff-base Zn complex exhibited higher anticancer activity than the LMW-chitosan Zn complex. Combining LMW-chitosan with Schiff-base and Zn improved its anticancer activity, which we ascribe to the synergistic effect between the chitosan matrix and the planar construction of the Zn complexes.

Preparation and catalytic activity of polymer-bound 1,10-phenanthroline and its complexes

Abstract Polymer-bound 1,10-phenanthroline (PS-phen) has been prepared by reaction of chloromethylated polystyrene with 5-amino-1,10-phenanthroline. The polymer-bound ligand and its complexes (PS-phenFephen) were characterized by IR spectroscopy and XPS. The polymer bound ferric complexes, which are N , N , N , N -type complexes, show high catalytic selectivity in the oxidation of substituted benzene.

One-pot facile synthesis of half-cauliflower amphiphilic Janus particles with pH-switchable emulsifiabilities

A facile synthesis strategy for generating two types of highly uniform amphiphilic polymer Janus particles, spherical seeds and half-cauliflower particles, is first presented. Both of the submicron particles possessing pH-switchable emulsifiabilities can change their amphiphilicities/shapes and induce phase inversion of emulsions in response to pH values of solution.

Preparation and catalytic activity of polymer bound benzotriazole copper complexes

Abstract The polymer-bound benzotriazole (P-BTA) was prepared from p-chloromethylated polystyrene resin, benzotriazole and anhydrous K2CO3 under phase transfer catalysis. The polymer complex (P-BTA-Cu) was synthesized with P-BTA and metal salts (Cu(OAc)2·H2O), and was characterized by IR spectra, XPS, TG-DTA and elemental analysis, which showed that the polymer was stabilized by benzotriazole. The polymer complexes (P-BTA-Cu) have been applied in oxidation of the α-carbon of aromatic hydrocarbon with O2. The reaction was carried out under 1 atm of O2, which gives α-methylbenzyl alcohol and acetophenone for ethylbenzene.

Loess clay based copolymer for removing Pb(II) ions.

Functional monomers, such as acrylic acid and 2-hydroxyethyl methacrylate were supported into loess clay in situ polymerization, which afforded loess clay based copolymer (LC/PAAHM), a new kind of polymer adsorbent for removing Pb(II) ions from aqueous solution. Characterization of the polymer adsorbent was carried out by different sophisticated methods, such as Fourier transformation infrared spectrometry (FTIR), scanning electron microscopy (SEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), and Zetasizer. Batch experiments were carried out to evaluate the factors affecting the removal efficiency, in which the pH, the adsorbent dosage, temperature and initial Pb(II) concentration all found in positive relevance to the increase of Pb(II) removal efficiency. The removal rate of Pb(II) got to 99% at room temperature and the adsorption capacity got to 356.9 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data, and Langmuir and Freundlich models have been applied to study the adsorption equilibrium, respectively.

Keratin films from chicken feathers for controlled drug release.

Abstract summaryDuring the past two decades significant advances have been made in the development of biomaterials for biomedical applications, especially biomaterials based on natural polymers. In this paper, we report the preparation of protein films for controlled drug release applications. This

Study on oxidation mechanism of cumene based on GC-MS analysis

Based on the gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) spectra, the analysis of the products of the catalytic oxidation and its mechanism can be elucidated. Here, the analysis of the aerobic oxidation products of cumene catalyzed by the polymer ferric complex through GC-MS has been performed. The main products are 2-phenyl-2-propanol (PP), 2-phenyl-2-iso-propyl hydroperoxide. From the analysis, the radical reaction mechanism was presumed. The relationship between the selectivity of cumene hydroperoxide and PP has been studied.