生物降解聚氨酯切花泥的研制

用魔芋部分代替聚醚多元醇,及甲苯-2,4-二异氰酸酯为主要原料合成了具有较高吸水性、保水性和可生物降解型聚氨酯泡沫。考察了异氰酸指数,硅油用量、反应温度对合成的影响。结果表明最佳的制备条件为魔芋精粉、PPG-3000、甘油为混合聚醚、异氰酸指数1.134;硅油3%、油浴40~50℃、搅拌8h。合成的聚氨酯泡沫有较高吸水性、保水性和生物降解性能,适合用做生物降解切花泥。     

聚乳酸-氨基酸共聚物的合成及表征

以乳酸（LA）、氨基酸（赖氨酸,L-L）、聚乙二醇（PEG）为单体,氯化亚锡（SnCl2）为催化剂,采用直接熔融缩聚法合成了医用生物可降解材料。通过四因素三水平的正交实验得出聚乳酸-氨基酸共聚的最佳反应条件为：LA、氨基酸（赖氨酸）、PEG的摩尔比为85∶10∶5,催化剂m（SnCl2）∶m（LA）=0.007,聚合时间为10h,聚合温度为110℃。产物的最大室温特性黏度为0.2197dL/g。     

Caseinate films modified with tung oil

Sodium caseinate/tung oil composite films were prepared through emulsification in order to reduce the water affinity of the protein-based film. Addition of lipid leads to milky films, resulting in a sharp increase in opacity. Uneven lipid distribution was evidenced by SEM in films prepared with 15% tung oil, which most likely arose from the limited dispersion capability of the lipids. Tung oil content also affects the film mechanical response, increasing tensile strength and elastic modulus but decreasing deformability. Contact angle measurements, besides water absorption tests, confirm lower hydrophilicity of the samples. However, tung oil incorporation into the caseinate matrix did not affect significantly the WVP at any of the three levels used, probably due to pore formation. The advantages of cross-linking composite films using heat were also addressed.     

Rheological behavior and bonding performance of an alkaline soy protein suspension

The goal of this work is to study the rheological properties of based-modified soy protein concentrate (SPC) adhesives and the relationship between viscoelastic properties and bonding performance. Chemical modification of SPC with sodium hydroxide was made to evaluate the effect of alkali on the viscoelastic proper ties. Viscosity and solubility depends directly on the 3D structure and the isoelectric point (pI) of the protein. Results show that viscosity is strongly pH dependent due to the protein unfolding. Solubility profiles exhibit the typical U-shaped curve, being higher on either side of the isoelectric point. Fourier transformed infrared analysis was used to analyze Amide I (1720–1600 cm⁻¹) and Amide III (1400–1200 cm⁻¹) band patterns which reflect the different secondary structures in proteins. The intensity of the band at 1250 cm⁻¹ increases with respect to that at 1235 cm⁻¹ for higher pH values. This could be associated with the destruction, at least partially, of the β-sheet structure. Bonding performance was measured in dry conditions and the wetting properties were analyzed by scanning electron microscopy. The bonding performance improves when the SPC is stabilized at pH 12 due to the protein unfolding, revealing a strong interaction between the secondary structure and the wood surface. As part of an ongoing project it was concluded that alkali modification is a suitable procedure to modify a protein suspension, improving application conditions and mechanical properties of bioadhesives of a semistructural type.     

A facile construction method for pH and oxidation dual-responsive assembly based on ferrocene-modified chitooligosaccharide

Here, we present a novel and facile method for constructing “snowflake-like” assemblies that respond to external stimuli, similar to snowflakes in nature, via the self-organization of ferrocene-modified chitooligosaccharide (FcCOS) in an acid aqueous solution. Interestingly, the snowflakes were sensitive to pH and redox stimuli. They not only formed irregular network-like aggregates when the pH was adjusted to 7.0, they also gradually transformed into loose snowflakes with holes after exposure to air for 5 d and totally collapsed after treatment with hydrogen peroxide. Due to their interesting responses to pH and oxidation, these assemblies are a very interesting and promising system for biomaterial applications.     

A Novel of Biodegradable Implants Based on PLGA for Control Delivery of Cisplatin

A novel controlled drug delivery micro-device was successfully prepared with biodegradable implants based on PLGA by solvent evaporation method. The micro-chambers were fabricated using the UV-LIGA technology. The controlled release process resulted from the design of the micro-chambers and the characteristics of biodegradable polymers. Implant bioactivity was tested using in vitro and in vivo release. The implants kept good shape and cisplatin was homogeneous loaded in the PLGA implants. The precast implants appeared hexagon. With different proportion of PLA and PGA segment, the swelling behavior and the hydrolytic degradation rate of implants became lower due to the increase of PLA hydrophobic segment. In vitro and in vivo drug release behavior was studied using cisplatin as model drug, the implants could control the diffusion of cisplatin. The results demonstrated that this type of controlled drug delivery micro-device could be more potential application in tumor therapy.     

油脂的化学和生物转化研究进展

综述了近年来发现的一些新型脂肪酸的结构和应用,以及游离脂肪酸包括长链脂肪酸、ω-羟基脂肪酸和ω-不饱和脂肪酸的合成与化学转化现状,概述了生物学方法特别是酶催化法在油脂转化方面的研究进展。     

Assessment of Edible Fungi and Films Bio-Based Material Simulating Expanded Polystyrene

Expanded polystyrene (EPS) contains benzene and styrene, posing a risk to human health. Research objective was to create and evaluate a bio-based material that mimics EPS physical and mechanical properties; this material was developed from crop residues (Triticum sp.), fungi (Pleurotus sp.), and edible films (carrageenan, chitosan, and xanthan gum). Treatments differed in the type of film applied over the bio-based material, and physical and mechanical properties were evaluated. Compressive and flexural strength ranged from 20 to 60 kPa and 4.6 to 17.9 kPa, respectively; dimensional stability and relative density ranged from 5.1 to 7.3% and 178.7 to 198.9 kg m^?3, respectively. The bio-based material does not pose to be an alternative to EPS yet, and further researches must assess water absorption and biodegradability.     

Formulation and evaluation of injectable in situ forming microparticles for sustained delivery of lornoxicam

The objective of this study is to formulate biodegradable in situ microparticles (ISM) containing lornoxicam for post-operative and arthritic pain management. ISM emulsions were prepared according to 2⁵ full factorial experimental design to investigate the influence of formulation variables on the release profile of the drug. The independent variables studied are the polymer type, polymer inherent viscosity, polymer concentration, oil type and polymer:oil ratio. In vitro drug release, microscopical examination, particle size determination and syringeability measurement were selected as dependent variables. The effect of γ-sterilization on the prepared formulae was also examined. The prepared formulae showed extended drug release over two weeks, and flow time below 5?s/ml. Scanning electron microscope revealed that the prepared microparticles were spherical in shape, with diameter ranging from 3.45 to 22.78?µm. In vivo pharmacokinetic evaluation of two selected optimum formulations in rabbits showed prolonged drug absorption indicated by delayed T_max and the extended mean residence time. In conclusion, the prepared injectable ISM could be a promising approach for providing extended delivery of lornoxicam with low initial burst effect.     

可生物降解高分子材料研究进展

简要说明了可生物降解高分子的降解机理及其种类,介绍了可生物降解高分子材料及其在生物医药方面的应用。表明可生物降解高分子具有良好的应用前景。