Methoxypoly (ethylene glycol)- block-poly (DL-lactide) (PELA) microcapsules containing bovine hemoglobin (BHb) were prepared by a W/O/W double emulsion-solvent diffusion process. The P50 and Hill coeffcient were 3466 Pa and 2.4 respectively, which were near to the natural bioactivity of bovine hemoglobin. The results suggested that polymer composition had significant influence on encapsulation efficiency and particle size of microcapsules. The encapsulation efficiency could reach 90% and the particle size 3 - 5 microm when the PELA copolymer containing MPEG 2000 block was used. The encapsulation efficiency and particle size increased with the concentration of PELA. Increasing the concentrations of NaCl in outer aqueous solution resulted in the increase of encapsulation efficiency and the decrease of particle size. As the concentration of stabilizer in outer aqueous solution increased in the range of 10 g/L to 20 g/L, the particle size reduced while encapsulation efficiency was increased, further increase of the stabilizer concentration would decrease encapsulation efficiency. Increasing of primary emulsion stirring rate was advantageous to the improvement of encapsulation efficiency though it had little influence on the particle size. The influence of re-emulsion stirring rate was complicated, which was not apparent in the case of large volume of re-emulsion solution. When the wall polymer and primary emulsion stirring rate were fixed, the encapsulation efficiency decreased as the particle size reduced.
Animals ; Biocompatible Materials ; chemistry ; Capsules ; Cattle ; Hemoglobins ; metabolism ; Lactates ; chemistry ; Particle Size ; Polyethylene Glycols ; chemistry ; Technology, Pharmaceutical ; methods

The lipase labeled with the fluorescein isothiocyanat (FITC) was immobilized on the derivatives of the polyethylene glycol. The article discussed the effect of factors on the characters of lipase and analyzed the relationships among the activity of lipase, conformation, and fluorescence spectrum while the activity and the fluorescence spectrum of immobilized lipase were determined. The results demonstrated that polyethylene glycol 400-diacrylate could form appropriate network to improve the activity of enzyme. Adding ligand induced the lipase's catalytic conformation to increase the activity twice more than before. The active centre of lipase could be released by the extraction of ligand thus increasing the activity. After immobilization, the stability of labeled lipase improved greatly: immobilized lipases retained more than 70% and 60% of initial activity under conditions of 90 degrees C and strong acid or alkali, respectively. After immersing immobilized lipases into guanidine hydrochloride or urea for 15 days, the lipases retained upwards of 70% activity. The fluorescence spectrum could obviously reflect the changes of the activity and conformation of lipase. The fluorescence intensity was the minimum in the optimal pH and temperature. In the denaturing agent it declined as time passed. These results indicated that the unfolded processes of immobilized lipases are different under different conditions.
Dextrans ; chemistry ; Enzyme Stability ; Enzymes, Immobilized ; chemistry ; metabolism ; Fluorescein-5-isothiocyanate ; analogs & derivatives ; chemistry ; Fluorescent Dyes ; chemistry ; Lipase ; chemistry ; metabolism ; Polyethylene Glycols ; chemistry ; Protein Unfolding ; drug effects

Fermentation and induction conditions for recombinant Escherichia coli expressing Thermobifida fusca cutinase were optimized in flasks and 3L fermenter. Surface modification of poly (ethylene terephthalate) fibers with cutinase was also discussed. The results showed that, cutinase yield reached 128 U/mL by adding 2 g/L inducer lactose and 0.5% glycine. In the fed-batch culture in a 3 L fermenter, the maximum biomass cutinase activity was up to 506 U/mL, which is the highest bacterial cutinase activity reported by far. Recombinant cutinase was used to modify polyester fibers and terephthalic acid substance was detected by using UV analysis. The dyeing and wetting properties of cutinase treated fibers were higher than untreated fibers. Combined utilization of cutinase and Triton X-100 can significantly improve the hydrophilicity of polyester. This is the first report of surface modification on polyester fibers by bacterial cutinase.
Actinomycetales ; enzymology ; genetics ; Carboxylic Ester Hydrolases ; biosynthesis ; chemistry ; genetics ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Polyethylene Glycols ; chemistry ; Polyethylene Terephthalates ; Recombinant Proteins ; biosynthesis ; genetics ; Surface Properties

The present research was to study the biocompatibility of a composite of hydroxyapatite (HA), carbon fiber (CF) and polyetheretherket-one (PEEK) by co-culturing with the osteoblasts in vitro. Cell relative growth (RGR) was used as a quantitative assessment for cytotoxicity of the biomaterials by CCK-8. The proliferation index of the co-cultured cells and ALP activity was measured to study the effect of PEEK-HA-CF composites. Morphological properties of the osteoblast cells in vitro were observed by scanning electro-microscopy (SEM). The PEEK-HA-CF materials have no cytotoxicity to osteoblasts. The proliferation index of PEEK-HA-CF was higher than that of Ti alloy group, but these was no significant difference compared to that of control group. The ALP activity was the highest on PEEK-HA-CF composites surface after 7 days. The osteoblast cells co-cultured with the PEEK-HA-CF composite were adhered well to the biomaterial as observed under the SEM. The results suggested that the PEEK-HA-CF composites had good biocompatibility in vitro and might be a novel orthopedic implanted material.
Alkaline Phosphatase ; metabolism ; Animals ; Biocompatible Materials ; Carbon ; chemistry ; Cell Proliferation ; drug effects ; Cells, Cultured ; Durapatite ; chemistry ; Ketones ; chemistry ; Orthopedics ; Osteoblasts ; chemistry ; Polyethylene Glycols ; chemistry ; Prostheses and Implants ; Rats

Liposome-mediated nucleic acid delivery has been a focus recently, but in the course of delivering nucleic acid, some hurdles seriously limit the nucleic acid exerting treatment effect. This review refers to a series of problems such as low blood stability, reticuloendothelial system absorption, the lower targeting of liposome and the restriction of endosomal escape which are suffered in liposome-mediated nucleic acid delivery; and gives a detail introduction of strategies such as PEGylation, ligand modification, photochemical internalization, the application of degradation liposome and membrane-lytic peptide, to overcome those problems.
Animals ; Humans ; Liposomes ; chemistry ; pharmacokinetics ; Mononuclear Phagocyte System ; metabolism ; Nanoparticles ; Nucleic Acids ; chemistry ; pharmacokinetics ; Photochemical Processes ; Polyethylene Glycols ; chemistry ; pharmacokinetics ; Polymers ; chemistry

OBJECTIVETo investigate the effects of labrasol, solutol HS 15 and transcutol P on the corneal permeability of mangiferin in vitro.

METHODThe effects of three penetration enhancers on the corneal permeability of mangiferin were investigated in vitro by using isolated rabbit corneas.

RESULTThe apparent Papp enhancements were increased 1.80, 3.27, 3.41 and 4.76-folds with Lab at 1.0%, 1.5%, 2.0% and 3.0% (P < 0.01), respectively. The apparent Papp increased 1.98 and 3.07-folds with Sol at 0.2% and 0.4% (P < 0.01), respectively, but reduced with 0.010%-0.03% Trans.

CONCLUSIONThe Papp value of mangiferin is significantly enhanced by 1.0%-3.0% Lab, 0.2% and 0.4% Sol, however the Papp value of mangiferin is reduced by 0.01%-0.03% Trans.

Animals ; Cornea ; drug effects ; metabolism ; Drug Carriers ; chemistry ; Ethylene Glycols ; chemistry ; Glycerides ; In Vitro Techniques ; Organic Chemicals ; chemistry ; Permeability ; Plant Extracts ; pharmacokinetics ; Polyethylene Glycols ; chemistry ; Rabbits ; Stearic Acids ; chemistry ; Xanthones ; pharmacokinetics

To investigate if the surface modification of intraocular lens (IOL) is efficient in the prevention of posterior capsular opacification (PCO), the acrylic surface of intraocular lens (Acrysof(R)) was polymerized with polyethylene glycol (PEG-IOL). The human lens epithelial cells (1x10(4) cells/mL) were inoculated on PEG grafted or unmodified acrylic lenses for the control. The adherent cells on each IOL surface were trypsinized and counted. The every PEG-IOL was implanted in 20 New Zealand rabbits after removal of crystalline lens. The formations of PCO were checked serially through retroilluminated digital photography, and the severity scores were calculated using POCOman(R). The cell adherence patterns on each IOL were examined by scanning electron microscopy. As a result, the mean number of adherent cells of PEG-IOL (3.2+/-1.1x10(3)) tended to be smaller than that of the acrylic controls (3.6+/-1.9x10(3)) without a statistical significance (p=0.73). However, the mean severity of PCO formation in PEG-IOL was significantly lower than that in the control during the third to sixth weeks after surgery. Scanning electron microscopy revealed that the more patch-like cells were found firmly attached to the IOL surface in control than in the PEG-IOL. Conclusively, PEG polymerization to the acrylic IOL would possibly lessen the formation of PCO after cataract removal.
Acrylic Resins/chemistry ; Biocompatible Materials ; Cataract/metabolism/*therapy ; Cell Adhesion ; Humans ; Lens Implantation, Intraocular/*methods ; Lens, Crystalline/cytology/ultrastructure ; Microscopy, Electron, Scanning ; Polyethylene Glycols/*chemistry/metabolism ; Time Factors

The core-crosslinked polymeric micelles were used as a new drug delivery system, which can decrease the premature drug release in blood circulation, improve the stability of the micelles, and effectively transport the drug into the therapy sites. Then the drug bioavailability increased further, while the side effect reduced. Most drugs were physically entrapped or chemically covalent with the polymer in the internals of micelles. Based on the various constitutions and properties of polymeric micelles as well as the special characteristics of body microenvironment, the environment-responsive or active targeting core-crosslinked micelles were designed and prepared. As a result, the drug controlled release behavior was obtained. In the present paper, the research progress of all kinds of core-crosslinked micelles which were published in recent years is introduced. Moreover, the characteristic and application prospect of these micelles in drug delivery system are analyzed and summarized.
Animals ; Antineoplastic Agents ; administration & dosage ; chemistry ; therapeutic use ; Cross-Linking Reagents ; chemistry ; metabolism ; Drug Carriers ; chemistry ; metabolism ; Humans ; Micelles ; Molecular Structure ; Neoplasms ; drug therapy ; Particle Size ; Pharmaceutical Preparations ; administration & dosage ; Polyethylene Glycols ; chemistry ; metabolism ; Polymers ; chemistry ; metabolism

The ischemic heart disease has been endangering human health seriously. Although there are many kinds of anti-ischemic drugs, most of them are lacking in tissue specificity, which together with a remarkably reduced blood circulation in the ischemic zone often lead to a quite low drug distribution in the targets. Myocardial ischemia can cause a lot of pathophysiological changes, such as the enhanced permeability of the endothelial cell membrane, the up-regulated expression of various cell adhesion molecules on endothelium, the exposure of intracellular antigenic components, the decrease of pH within the ischemic zone, and so on. To date, some of these changes have been exploited with limited success to gain the passive, active and physicochemical targeting of diagnostic or therapeutic drugs to myocardial ischemic regions. However, more effective delivery strategies are still eagerly needed. Here, we reviewed and discussed the potential targeting-delivery mechanisms and strategies, used or may be used in the future, for myocardial ischemic regions.
Animals ; Antibodies, Monoclonal ; immunology ; Capillary Permeability ; Drug Carriers ; Drug Delivery Systems ; methods ; Genetic Therapy ; Humans ; Liposomes ; chemistry ; metabolism ; Myocardial Ischemia ; therapy ; Myocardium ; metabolism ; pathology ; Polyethylene Glycols ; metabolism ; Ultrasonics

A novel transformation method was firstly established using glass beads in Dunaliella salina (D. salina). The results showed that the GUS gene, a reporter gene, was successfully expressed in D. salina. Cells of D. salina presented blue color under the microscope after stained. In addition, different factors which influenced transformation were optimized including the transformation consecutive time, rotate speed, concentration of the plasmid and PEG 6000. The experiment indicated that this fit together can obtain the best results for D. salina transformation: adding 150 microL PEG and 90 microL plasmid DNA to 800 microL culture of D. salina (10(6) cells/mL) containing 300 mg glass beads, swirling 12 seconds under the rotate speed 2400r/min. This newly method can be used as a potential tool in the research of D. salina gene engineering with the advantage of more simpleness, convenience, quickness and less expense.
Chlorophyta ; genetics ; DNA ; chemistry ; genetics ; Genetic Engineering ; methods ; Glass ; Glucuronidase ; genetics ; metabolism ; Histocytochemistry ; Microspheres ; Plasmids ; genetics ; Polyethylene Glycols ; chemistry ; Time Factors ; Transformation, Genetic ; genetics