Natural Bioactive Material: A Preparation of Soluble Eggshell Membrane Protein

The proteins of eggshell membranes, an industrial waste product, are dissolved by reductive cleavage with aqueous 3‐mercaptopropionic acid and acetic acid. The soluble protein preparation is cast into a thin film, and its bioactivity is investigated by cell culture.

Photomicrograph of NIH3T3 fibroblasts cultured on SEP film for 3 days.     

生物医用磷脂化聚氨酯的设计、制备与性能

聚氨酯因其具有优异的力学性能和良好的生物相容性广泛地应用于医疗领域.但医用聚氨酯常常会引起蛋白吸附、血小板激活、凝血、血栓和补体激活等不良生物学反应,使其应用受到限制.仿生物膜的磷脂表面被认为是和人体最亲和的表面,聚氨酯磷脂化是提高医用聚氨酯材料生物相容性的非常有效的手段之一.近年来国内外课题组在生物医用磷脂化聚氨酯的设计、制备与生物相容性等方面开展了大量的工作,取得了重要的研究进展.本文综述了磷脂改进医用聚氨酯的最新研究成果,指出含氟磷脂化聚氨酯和可降解的磷脂聚氨酯因其优异的性能,代表了该领域的发展方向并具有重要的应用前景.     

Low Viscosity Poly(trimethylene carbonate) for Localized Drug Delivery: Rheological Properties and in vivo Degradation

The purpose of this study is to examine the potential of low‐molecular‐weight poly(trimethylene carbonate) for localized delivery for acid‐sensitive drugs. Poly(trimethylene carbonate) of various molecular weights is prepared by ring‐opening polymerization initiated by octan‐1‐ol and co‐initiated/catalyzed by tin 2‐ethylhexanoate. The resultant polymers are amorphous with low glass transition temperatures and viscosities at 37 °C that permit their injection through an G 1.5″ needle. Their biocompatibility and the influence of the molecular weight on the rate of degradation are assessed in vivo through subcutaneous implantation in rats over 40 weeks. The polymers are well tolerated in vivo, and degrade in a fashion dependent on their initial molecular weight. For very low initial molecular weight (620 Da) and for high initial molecular weight (2 400 Da), polymer mass loss is a result of dissolution of the soluble low molecular chains from the bulk. This is contrasted by the results obtained for an intermediate initial molecular weight (1 600 Da), for which polymer mass loss is a result of both dissolution and enzymatic hydrolysis or oxidation as a result of reactive species secreted by activated macrophages at the implant surface.

     

Fabrication of Bioactive Polyoxymethylene Nanocomposites for Bone Tissue Replacement

Summary: Stearic acid modified nano hydroxyapatite (n-SHA) filled polyoxymethylene (POM) nanocomposites were prepared by melt mixing method for bone tissue replacement and regeneration applications. Contact angle measurements of POM nanocomposites were carried out to understand the effect of n-SHA addition on the hydrophobicity of nanocomposites. The mechanical properties like tensile strength, Young's modulus and elongation at break were found to be increased significantly by the incorporation of n-SHA into the POM matrix. The bone-bonding ability of the nanocomposites was evaluated by examining the apatite formation on their surface after soaking in simulated body fluid (SBF) and apatite formation was studied by atomic force microscopy (AFM). The protein adhesion studies revealed the enhanced biocompatibility of the nanocomposites due to the presence of n-SHA nanofillers on the surface and it provides favorable binding sites for protein adsorption. The significant improvement in the biocompatibility as well as mechanical, thermal and hydrophobic properties of the POM nanocomposites makes it a potential future material for bone implantation.     

A general model for the release of active agents incorporated in swellable polymeric matrices

A theoretical model, which takes proper account of the simultaneous uptake of a liquid leachant by a polymer matrix and the consequent release of a bioactive or other solute incorporated therein, is presented and the kinetics of release predicted under various conditions is investigated. This model is shown to be both more rigorous and much more widely applicable than previous attempts to approach the above problem. Furthermore, it can be easily modified or extended, in accordance with the information available about any particular system. It is, therefore, expected that the model introduced here will prove useful as a basis for the design of monolithic controlled-release devices of this type or for the evaluation of the leachability of low-level and medium-level radioactive wastes “immobilized” in polymeric matrices.     

Synthesis and characterization of novel h‐HTBN/PEG PU copolymers: effect of surface properties on hemocompatibility

This work reported the hydrophilicity, hemocompatibility, and cytotoxicity of novel polyurethane (PU) scaffolds for tissue engineering, especially the hydrolysis effect of a soft‐segmented component, a hydrolytically‐modified hydroxyl‐terminated poly(butadiene‐co‐acrylonitrile) (h‐HTBN), on these properties. The PU copolymers were prepared by coupling poly(ethylene glycol) (PEG) with the h‐HTBN together with the help of 1,1‐methylene bis‐(4‐isocyanatocyclohexane) as a bridging reagent. The structure of PU copolymers was characterized by Fourier transformation infrared spectrometry (FTIR). The experimental results indicated that the hydrolytically‐modified HTBN increases water absorption and decreases water contact angles, improving surface hydrophilicity. The synthesized h‐HTBN/PEG PU copolymers display low hemolysis activity, and a little amount of platelet adhesion and activation, implying good compatibility. The methyl tretrazolium (MTT) assays elicited that the cytotoxicity is related to the component ratios of h‐HTBN to PEG and the hydrolysis modification of HTBN. The PU scaffolds can be employed as potential candidates for blood contacting applications. Copyright © 2009 John Wiley & Sons, Ltd.     

Metal complexes with polymeric ligands: modular synthesis of multifunctional materials for applications in biomedicine and nanotechnology

Polymeric metal complexes exhibiting useful properties were prepared by chelating macroligands to labile and inert metal ions. The specific structures elucidated through this method, as well as potential applications for these complexes are described. By carefully selecting the appropriate metal ion and polymer, these materials can be tuned for a host of applications in fields ranging from biomedicine to nanotechnology.     

Solid-phase synthesis and evaluation of TAR RNA targeted beta-carboline-nucleoside conjugates

Four types of beta-carboline-nucleoside conjugates were synthesized. The binding affinities of these beta-carboline-nucleoside conjugates , and to TAR RNA were evaluated by affinity capillary electrophoresis. The data of binding affinities to TAR RNA show that conjugates and are stronger binders than the parent compound . Computer modeling indicates that the beta-carboline-nucleoside conjugate can fit to the UCU three-nucleotide bulge region of TAR RNA.     

Solid acid catalysts for synthesis of biodiesel fuel from pyrolyzed natural and synthetic polymeric materials

New heterogeneous catalysts for synthesis of a biodiesel fuel, modified with strongly acidic groups, were developed. The catalysts are produced by pyrolysis and subsequent sulfation of fruit kernels and granulated porous copolymers and resins. The structural-sorption and catalytic properties of the materials obtained were studied in the reaction of catalytic re-esterification of rapeseed oil by methanol and ethanol. The conditions in which carbon materials with high content of surface acid groups are obtained were optimized.     

Biocompatibility and structural stability of a laminin biopolymer

Polylaminin (polyLM) is a polymerized form of the extracellular matrix protein laminin obtained upon pH acidification. Here microscopy and spectroscopic tools are used to study the cell compatibility and the structural stability of polyLM, aiming at establishing its robustness as a biopolymer for therapeutic use. PolyLM is cell compatible as judged by the efficiency of attachment and neuritogenesis. It is resistant to low temperature. Addition of urea or an increase in hydrostatic pressure leads to polymer disassembly. PolyLM biofilms remain stable for 48 h in contact with cell culture medium. The sedimented polymer recovered after centrifugation and adsorbed on a glass coverslip preserved its original structure and its biological properties.

     

The synthesis and evaluation of trimeric X-ray contrast agents

Novel trimeric iodinated contrast agents with low osmolality have been prepared and evaluated with the aim of improving the already good safety profile of such agents. While the aim of low osmolality was achieved, the viscosity of the trimeric agents was found to be generally higher than current dimeric agents in clinical use.     

Tubulin targeted antimitotic agents based on adamantane lead compound: synthesis,SAR and molecular modeling

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Short-term evaluation of the thermal endurance characteristics of polymeric materials by TA

Two thermal analysis techniques (isothermal differential calorimetry and isothermal thermogravimetric analysis) are used as analytical methods for short-term thermal endurance characterization of polymeric materials, used for electrical insulation. These techniques are applied to commercial grade ethylene-propylene rubber and polyvinyl chloride. It is shown that thermogravimetric analysis provides very satisfactory results, independently of the degradation reactions which take place in the material. Calorimetry proves to be effective only for polymers (such as polyolefins) in which oxidation is the largely prevailing degradation mechanism in the test and service temperature ranges. This revised version was published online in July 2006 with corrections to the Cover Date.     

Algorithm for preliminary evaluation of the correlation time of local dynamics in some polymeric materials

A method for preliminary evaluation of the correlation time of local dynamics of the polymeric chains, using the experimental nuclear magnetic resonance spin-lattice relaxation data, is proposed. The algorithm is based on the model of the passage of a particle over a potential energy barrier. This method was utilized for some molten polymers and concentrated polymeric solutions.     

Artificial polymeric flavonoids: synthesis and applications

Flavonoids, one of the most numerous and best studied groups of plant polyphenols, are well known to exhibit various biological and pharmacological effects. Functional artificial polymeric flavonoids, flavonoid polymers and amine containing polymer-flavonoid conjugates have been developed. The acid-catalyzed polymerization of catechin and aldehydes proceeds regioselectively to produce catechin-aldehyde polycondensates. Peroxidases and laccases catalyze the oxidative coupling of flavonoids and oxidative conjugation with polyamines. The resulting polymers show much higher antioxidant activities than the flavonoid monomers. In addition, these polymeric flavonoids efficiently inhibit disease related enzymes, such as xanthine oxidase, collagenase, elastase, hyaluronidase and tyrosinase. Based on these results, the molecular design for amplification of the biological and pharmacological properties of flavonoids is proposed.     

Synthesis and Properties of Polycarbosilanes Having Lactose‐Derived Structures

A polycarbosilane having lactose‐derived structures was synthesized, and its thermal property, cytotoxicity, chemical crosslinking, and protein adsorption properties were investigated. The polycarbosilane (PSB‐Lac) was prepared by a thiol‐ene reaction between precursor poly(1‐(3‐butenyl)‐1‐methylsilacyclubane) (PSB) and heptaacetyl lactose that carried a thiol group at the anomeric position, and the successive deprotection of the acetyl groups. The lactose introduction efficiency determined by ¹H NMR measurement was 75%. TGA and DSC revealed that the polymer had a 5 wt% decomposition temperature of 260 °C and glass transition temperature (T_g) of 84 °C, which indicated that PSB‐Lac was a thermally stable polymer. PSB‐Lac had no significant cytotoxicity, which was evaluated by human liver cancer cell line HepG2 cultivation on the polystyrene dishes coated with the polymer. Urethane‐crosslinked PSB‐Lac films were prepared by casting solutions of PSB‐Lac and hexamethylene diisocyanate and heating at 120 °C after evaporation of the solvent. The crosslinked PSB‐Lac showed higher adsorption of bovine serum albumin than the similarly crosslinked polycarbosilane that had a glucose structure (PSB‐Glc). © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2420–2425