医用生物活性材料的研究

本文以CaO-Al_2O_3-P_2O_5系统为基础玻璃;加入一定量的羟基磷灰石、磷酸氢钙,混合、成型后,经热处理而制得医用生物活性复合材料。用差热分析、X射线衍射分析、扫描电镜和电子探针X射线衍射分析鉴定了材料中的晶相和显微结构,并对该材料的气孔率、化学性质和弹性模量等性能进行了测试和分析。动物试验结果表明,此种材料具有良好的生物相容性和生物活性,是一种具有实用价值的新型人工骨材料。     

Antimicrobial hydrogels formed by crosslinking polyallylamine with aldaric acid derivatives

Aqueous dispersions (0.1 wt %) of hydrogels 1 and 5 —formed by crosslinking polyallylamine hydrochloride (MW 60,000) with aldaric acid derivatives, diethyl L ‐tartrate and N,N′‐bis(methoxycarbonylmethyl)‐D ‐glucaramide, respectively—exhibited complete (log 5) kill within 4 h of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans suspended in culture medium. This antimicrobial activity was much higher than that of uncrosslinked polyallylamine (1 wt % killed only 75% of E. coli in 24 h). When dispersed at 10 and 100 ppm, hydrogel 5 displayed complete (log 5) kill of E. coli within 30–60 and 15 min, respectively. Hydrogels 1 and 5 were active against S. aureus and Salmonella choleraesuis dried on hard stainless steel surfaces and accelerated the deaths of E. coli, P. aeruginosa, S. aureus, and C. albicans in a model skin cream formulation. A 0.8% aqueous dispersion of hydrogel 5 was also effective as a hand sanitizer, killing 99.7% of Serratia marcescens on human hands within 5 min. Hydrogels 1 and 5 caused no dermal irritation or allergic contact sensitization under the conditions of a human repeat insult patch test. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

多孔双相钙磷钛合金微弧氧化膜层的制备及生物相容性

为克服钛合金生物膜层单一相的缺陷,以Ti6A14V合金为基体,用微弧氧化法制得具有双相钙磷复合陶瓷膜层(BCP)的钛合金器件.通过控制工作液成分制得由不同比例的β-磷酸三钙(β-TCP)和羟基磷灰石(HA)组成的多孔性复合膜层.研究了电源占空比对BCP膜孔隙率和孔径大小的影响.采用能谱仪和X射线衍射仪分析了BCP膜层的...     

Role of choline formate ionic liquid in the polymerization of vinyl and methacrylic monomers

Polymerizations of vinyl and methacrylate monomers (2‐hydroxyethyl methacrylate, styrene, and methyl methacrylate) were carried out in a choline formate ionic liquid at room temperature without the addition of peroxide‐based initiators. Choline formate acted as both an initiator and a solvent and produced high‐molecular‐weight polymers. Gel permeation chromatography and electron paramagnetic resonance measurements indicated that the polymerizations predominantly occurred by a free‐radical mechanism. This method of polymerization provides an alternate route to eliminate the use of toxic initiators and solvents. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and degradation of sorbitol‐based polymers

A new class of biodegradable copolyesters was synthesized by the catalyst‐free melt condensation of sorbitol with citric acid, tartaric acid, and sebacic acid. The resulting polymers were designated as poly(sorbitol citric sebacate) [p(SCS)] and poly(sorbitol tartaric sebacate) [p(STS)]. The synthesized polymers were characterized by Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, and differential scanning calorimetry analysis. Porous spongelike scaffolds were prepared with a salt‐leaching technique and characterized with scanning electron microscopy. Tensile testing of the p(SCS) and p(STS) polymers showed that they exhibited a wide range of mechanical properties. The Young's modulus and tensile strengths of the polymers ranged from 1.06 ± 0.12 to 462.65 ± 34.21 MPa and from 0.45 ± 0.04 to 20.32 ± 2.54 MPa, respectively. In vitro degradation studies were performed on disc‐shaped polymer samples. The half‐life of the polymers ranged from 0.54 to 38.52 days. The percentage hydration of the polymers was in the range 9.36 ± 1.26 to 78.25 ± 1.91, with sol contents of 2–14%. At any given polymer composition, the Young's modulus and tensile strength of p(SCS) was higher than that of p(STS), whereas the degradation rates of p(SCS) was lower than that of p(STS). This was attributed to the structural difference between the citric and tartaric monomers and to the degree of crosslinking. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Controlling the morphology of polyurethane/polystyrene interpenetrating polymer networks for enhanced blood compatibility

Polyurethane (PU)/polystyrene (PS) IPNs were simultaneously synthesized at 80°C, controlling the reaction kinetics to change the morphology. Polymerization kinetics of styrene was controlled by the content of initiator, and that of polyurethane by the catalyst concentration. The effect of the initiator and the catalyst on the polymerization rate was analyzed by NMR spectroscopy and FTIR. Gelation time was also measured by using the advanced rheometric expansion system (ARES). Samples with sea‐and‐island morphology were obtained, when the polymerization rate of PS was relatively slow, and the phase separation time was long. When the polymerization rate of PS was relatively fast, and the phase separation time was short, cocontinuous morphology was obtained. The degree of phase separation and surface roughness decreased, as the rate of PU network formation was increased, and the phase‐continuity was increased. The in vitro blood‐compatibility tests showed that the surface roughness was an important factor on the adsorption of fibrinogens and platelets. A large amount of fibrinogens and platelets were adsorbed on the relatively rough surface of samples showing sea‐island morphology. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 379–387, 2002; DOI 10.1002/app.10358     

Novel biocompatible waterborne polyurethane using L‐lysine as an extender

Polyurethane (PU) prepolymers based on isophorone diisocyanates, dimethylolpropionic acid, and polycaprolactone were prepared and chain‐ extended in water using L ‐lysine (PU–L), ethylenediamine (PU–E), and their mixture (PU– L–E) as extenders, respectively. The produced emulsion exhibited satisfactory freeze/thaw stability. Films cast from emulsions exhibited excellent mechanical properties and good antiblood coagulation character. Although the water‐swelling ratio for 24 h for PU–L was higher than those of PU–L–E and PU–E, it possessed the smallest hydrolysis rate among the three samples. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2474–2480, 2002     

Swelling kinetics of a hydrogel of poly(ethylene glycol) and poly(acrylamide‐co‐styrene)

A hydrogel incorporating the hydrophilic polymer poly(ethylene glycol) and a copolymer of acrylamide and styrene was synthesized, and the dynamics of the water‐sorption process were studied. The effects of the composition of the hydrogel and the temperature of the swelling medium were investigated with respect to the water‐sorption characteristics of the hydrogel, and the kinetic parameters, including the swelling exponent and diffusion constant, were evaluated. The hydrogel was also judged for the antithrombogenic property of its surface. The experimental findings were explained on the basis of the core–shell polymeric structure of the hydrogel. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1419–1428, 2002     

Surface modification of poly‐L‐lactide by photografting of hydrophilic polymers towards improving its hydrophilicity

Poly‐L ‐lactide (PLLA) has been used to prepare scaffolds to guide tissue regeneration in tissue engineering research. However, one of the limitations to the use of PLLA as an ideal biomaterial is its high hydrophobicity. To improve the hydrophilicity of PLLA, hydrophilic polymers were grafted onto PLLA membrane surfaces through the combination of photooxidization in hydrogen peroxide and subsequent ultraviolet (UV)‐induced grafting copolymerization in the monomer solution. Three kinds of modified PLLA membranes (i.e., PLLA‐g‐polyhydroxyethyl methacrylate, PLLA‐g‐polyacrylamide, and PLLA‐g‐polymethacrylic acid) were obtained, resulting in the more wettable PLLA membranes. The occurrence of the grafting polymerization was confirmed by attenuated total reflectance infrared spectroscopy (ATR‐IR) and X‐ray photoelectron spectroscopy (XPS) analysis. Surface morphology of the modified PLLA membranes was studied by scan electronic microscopy (SEM). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2163–2171, 2002     

基于表面生物学改性的多孔状二氧化钛/磷灰石复合薄膜的制备

在钛合金表面采用微孤氧化得到一层多孔状的具有生物活性的二氧化钛，经随后水热处理可形成羟基磷灰石薄膜，提高钛合金表面的生物学性能，用SEM、XRD、EDX分析了薄膜的组织、结构和化学组成，同时考察了微弧氧化得到的二氧化钛膜的生物活性，结果表明，在室温条件下从含钙、磷离子的电解液中在钛合金基体上微弧氧化得到一层二氧化钛薄膜，蒸汽处理后得到具有生物活性的二氧化钛/羟基磷灰石复合薄膜，该膜多孔均匀，且生物活性高，有利于骨组织的吸附和生长。