Preparation of poly(sodium 4-styrene sulfonate) grafted magnetic chitosan microspheres for adsorption of cationic dyes.

A novel adsorbent with high adsorption capacity to remove cationic dyes was synthesized. Sodium 4-styrene sulfonate (SSS) was grafted polymerization on the surface of magnetic chitosan microspheres via -NH2/S2O82- surface initiating system, obtaining MCS-g-PSSS microspheres. The grafted microsphere was characterized by Fourier transforms infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, vibration sample magnetometer and the Brunauer-Emmett-Teller. Cationic dyes were adsorbed by MCS-g-PSSS and methylene blue(MB) was acted as a typical example. The adsorption performance was explored by varying experimental conditions. The results showed the maximal adsorption capacity was 989 mg/g at pH 1 at 25 °C. The pseudo-second order model was found to be applicable for the adsorption kinetics. The adsorption capacity increased with rising temperature and it decreased owing to adding of ions. The adsorption isotherms were the best fitted by Langmuir. MCS-g-PSSS for MB showed high adsorption capacity due to the strong electrostatic interactions and π-π stacking, which was explained by FTIR and XPS and was verified by DFT calculations. The degree of adsorption spontaneity increased with rising the temperature. The grafted MCS-g-PSSS microspheres had high adsorption capacity for various kinds of cationic dyes and excellent for remove MB in the aqueous solution.

[Electrical stimulation enhances viability of osteoblasts on conductive biodegradable material].

This study was aimed at exploring the viability of osteoblasts on conductive tissue engineering material. Conductive biodegradable Polyprrole/Polylactide (PPy/PLA) was prepared by emulsion polymerization. Scanning electron microscope (SEM) and spectroscopy showed evenly dispersed PPy in PLA. PPy/PLA membrane was found being able to keep conductive stability for more than one month to provide electric circumstances (ECs) for osteoblasts. SEM displayed that osteoblasts adhered and spread well on PPy/PLA. ECs of 12.5, 25, 50, 75, 100, 125, 150, 175, 200 microA/cm2 were separately used to stimulate osteoblasts for 24h, 48h, 72h and 96h. Methyl-thiazole-tetrazolium (MTT) assay after 24h revealed that 50 microA/cm2 evidently accelerated osteoblasts proliferation. Alkaline phosphatase (ALP) activity assay revealed that, 48h later, 50 microA/cm2, and 75 microA/cm2 promoted osteoblasts differentiation. 50 microA/cm2 enhanced osteoblasts mineration. Conclusively, 50 microA/cm2 can strengthen osteoblasts' function and promote their viability.

Preparation of sulfonate chitosan microspheres and study on its adsorption properties for methylene blue.

Dyes bring a lot of benefits to our lives, however, as common organic pollutants, they have destructive influences on the environment. Firstly, glutaraldehyde crosslinked chitosan microspheres (GCS) are prepared via inverse-phase suspension polymerization. Then, GCS microspheres are acted as the base material, ammonium persulfate (Aps) as the initiator, sodium styrene sulfonate (SSS) as anionic functional monomer, functional microspheres (GCS-g-PSSS) are prepared by surface grafting polymerization. The amount of monomer and Aps, temperature and reaction time is respectively explored. The chemical structures and physicochemical properties of functional microspheres were characterized by FT-IR, zeta potential, scanning electron microscope and X-ray photoelectron spectroscopy. The adsorption kinetic at different temperature and initial concentration is studied and fitted. The adsorption isotherms of GCS-g-PSSS for MB are explored at different pH, temperature and salinity. The adsorption capacity of GCS-g-PSSS for MB is 820.1 mg/g at 318 K. The adsorption isotherms at different temperature are fitted by Langmuir, Freundlich, Dubinin-Radushkevich and Temkin. Thermodynamic parameters imply that adsorption is a spontaneous and endothermic process. And this adsorbent has good reusability. The adsorption ability of GCS-g-PSSS microspheres is also excellent for other cationic dyes. Thus, GCS-g-PSSS microspheres might serve as a promising adsorbent for contaminated water scavenging.

Preparation of crosslinked poly (acryloyloxyethyltrimethyl ammonium chloride) microsphere and its adsorption and mechanism towards shikimic acid.

Shikimic acid (SA) is a key raw material for the synthesis of the antiviral drug, but its extraction and separation from plants is still limited. Crosslinked poly (acryloyloxyethyltrimethyl ammonium chloride, DAC) microspheres were synthesized via inverse-phase suspension polymerization. In the synthesizing, N,N'-methylene bisacrylamide (MBA) was used as crosslinker, cyclohexane as dispersed medium and span-60 as dispersants, obtaining CPDAC gel microspheres. The effect of polymerization condition on balling performance and the characteristics of CPDAC were examined. The adsorption properties of CPDAC towards SA were mainly explored and the data of adsorption isotherm were analyzed by using Langmuir, Freundlich, Temkin, Sips and Toth models. Furthermore, the adsorption mechanism was analyzed in depth, and the adsorption thermodynamics was also investigated. The results show that in order to prepare CPDAC, water phase must be added dropwise to oil phase, and the volume ratio of oil-water is more than 2:1. The mean diameter of CPDAC decreases with increasing span-60 and accelerating agitating rate. The strong electrostatic interaction is formed between quaternary ammonium nitrogen of CPDAC and COO- of SA. The adsorption kinetic data is fitted well with pseudo-first-order model. The adsorption ability is higher in aqueous water than ethanol, reaching 108mg/g, and Toth model is more suitable for describing the actual adsorption process. The adsorption of CPDAC towards SA is dependent on the pH value of the medium. The adsorption process is exothermic, the adsorption amount decreases with the increase of temperature, and the process is driven by enthalpy. The adsorption amount decreases with the increase of salinity. The reusability of CPDAC towards SA can keep 86.1% at the sixth cycle.

[Effects of extracts from different parts of Folium perillae (L.) Britt. on Hemorrheological parameters in rats].

In order to provide experimental data for the development and application of drug in clinic, we determined the effects of extracts from different parts of folium perillae (L. ) Britt. on hemorheological parameters, extracted from leaves (folium perillae), seeds (fructus perillae) and peduncles (caulis perillae). The results showed that all extracts from different parts of folium perillae (L. ) Britt. can significantly reduce the whole blood viscosity at low shear rate (10 s(-1)), erythrocyte aggregation index, erythrocyte electrophoresis index (P<0.05), and the whole blood reductive viscosity at low shear rate (10 s(-1)) (P<0.01). Extracts from folium perillae and caulis perillae can significantly decrease erythrocyte deformation index (P<0.05), whereas extracts from fructus perillae can not. Extracts from fructus perillae and caulis perillae can significantly decrease plasma viscosity at low shear rate(10 s(-1)), but extracts of folium perillae can not. Aspirin can only decrease the whole blood reductive viscosity at low shear rate and plasma viscosity (P<0.05). All extracts from different parts of folium perillae (L. ) Britt. had no significant effects on hematocrit, erythrocyte rigidity index, fibrinogen concentration , the whole blood viscosity and the whole blood reductive viscosity at middle and high shear rate (60 s(-1),120 s(-1)).

Preparation of grafted microspheres CPVA-g-PSSS and studies on their drug-carrying and colon-specific drug delivery properties.

Sodium 4-styrene sulfonate (SSS) was graft-polymerized on the surfaces of crosslinked polyvinyl alcohol (CPVA) microspheres in a manner of surface-initiated graft-polymerization by using cerium salt-hydroxyl group redox initiation system, obtaining the grafted microspheres CPVA-g-PSSS. The chemical structure and physicochemical characters of CPVA-g-PSSS microspheres were fully characterized with infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and zeta potential determination. The aim of this work is to constitute a novel colon-specific drug delivery system via molecular design by using CPVA-g-PSSS microspheres as the drug-carrying material and by taking metronidazole (MTZ) as the model drug. The drug-carrying ability and mechanism of the grafted microspheres CPVA-g-PSSS for MTZ were investigated. Finally, in-vitro release tests for the drug-carrying microspheres were conducted. The experimental results show that in an acidic medium, the grafted microspheres CPVA-g-PSSS exhibit strong adsorption ability for MTZ by driving of electrostatic interaction, and have an adsorption capacity of 112 mg/g, displaying the high efficiency of drug-carrying. The in-vitro release behavior of the drug-carried microspheres is highly pH-sensitive. In the medium of pH=1, the drug-carrying microspheres do not release the drug, whereas in the medium of pH=7.4, a sudden delivery phenomenon of the drug will occur, displaying an excellent colon-specific drug delivery behavior.

Constructing chiral caves and efficiently separating enantiomers of glutamic acid with novel surface-imprinting technique.

Dimethylaminoethyl methacrylate (DMAEMA) was first graft-polymerized onto the surfaces of micron-sized silica gel particles in the manner of "grafting from" in a solution polymerization system, obtaining the grafted particles PDMAEMA/SiO(2). Then, the molecular imprinting towards the grafted PDMAEMA was conducted with one enantiomer of glutamic acid (Glu), L-Glu, as template molecule and with 2,2'-dichlorodiethylether (DCEE) as crosslinking agent by adopting the novel surface-molecular imprinting technique established by our research group, and the single enantiomer (L-Glu) molecule-imprinted material MIP-PDMAEMA/SiO(2) was obtained. With another enantiomer of glutamic acid, D-Glu, as the contrast compound, the recognition property of MIP-PDMAEMA/SiO(2) for L-Glu was investigated in depth with both static and dynamic methods, and its ability to separate L-Glu and D-Glu in the racemic solution was examined. The experiment results show that the surface-imprinted material MIP-PDMAEMA/SiO(2) has fine recognition selectivity and binding affinity for l-Glu, whereas its ability to combine D-Glu is poor. The selectivity coefficient of MIP-PDMAEMA/SiO(2) for L-Glu with respect to D-Glu is equal to 3.30, displaying an excellent chiral separation result. It is obvious that in this study, the substance separation at the molecular configuration level has been realized successfully.