酚醛树脂基活性炭微球的电化学性能研究Ⅰ.酚醛树脂基微球制备过程的研究

选用线型酚醛树脂为原料，采用乳化法可制得微球。为了揭示微球的成型，考察了在制备过程中酚醛树脂乙醇溶液的浓度、搅拌速率、成球终温、固化剂及表面活性剂的数量对酚醛树脂基微球的影响。研究结果表明：微球球径随着树脂溶液浓度的降低而减小，亦随搅拌速率的降低而减小；当搅拌速率为400r／min左右，表面活性剂的浓度在0．28mol／L～0．74mol／L，固化剂量的质量分数为6．0％(基于酚醛树脂)时，可得到球形度良好的微球。在高于树脂软化点以上成球终温对成球影响不大。     

Prilling process applied to collagen solutions

Abstract

The present work concerns the preparation of microbeads of collagen by a prilling process.

Collagen is one of the main components of vertebrate proteins, especially in. such tissues as skin, tendons, placenta, … Furthermore, it has some properties which makes it interesting to use as a biomaterial: biocompatibility, biodegradability, high tensile strength, hemostatic power, participation to the wound healing.

The patented process which is developped in this paper combines two techniques :

? breaking of a capillary flow by prilling

and

? reticulation of collagen after oxydation with periodic acid.

It uses neither organic solvents, nor variation of temperature and allows the production of microbeads which can be utilized for many different medical applications.     

Simplified preparation of crude and functional coagulogen by thermal inactivation of serine proteases in Limulus amebocyte lysate and its application for rapid endotoxin determination

The effects of thermal treatment on Limulus amebocyte lysate (LAL) reagent were studied. Thermal resistances of enzymes and coagulogen in LAL reagent were evaluated by aggregometry and SDS-PAGE. Although enzyme activities of LAL reagent were completely lost after heating at temperatures above 60 °C for 10 min, gelating activities of coagulogen were retained even over 80 °C. Phenylmethanesulfonyl fluoride (PMSF; 1 mmol/mL), a strong non-specific serine-protease inhibitor, did not completely inactivate serine-protease activities of LAL. As a result, complete hydrolysis of coagulogen to coagulin was unexpectedly obtained. Solvent treatment of LAL was similar in effect to thermal treatment of LAL, but there were 2 problems: complete removal of solvent from samples and increased solution turbidity during preparation. To study the application of thermal-treated LAL, we conjugated it with titania particles. LAL-conjugated titania particles were obtained as small aggregates between titania nanoparticles and thermal-treated LAL (LAL-conjugated microbeads; LCM). When the mixture of LCMs and fresh LAL reagent was reacted with endotoxin an acute aggregation of LCMs was induced prior to the aggregate formation of LAL as monitored by stirring turbidimetry. This method, endotoxin microbeads aggregometry (EMA) may provide a rapid and sensitive method for endotoxin determination.     

微球型壳聚糖胺基吸附剂的制备及性能

以壳聚糖为原料,采用反相悬浮交联的方法制取微球型壳聚糖颗粒,再进行羟丙基氯化及胺基化,制备了一系列新型壳聚糖胺基衍生物微球。衍生物的胺基含量明显提高,碱性增强。并初步考察其吸附牛血清白蛋白（ＢＳＡ）性能。可用作新固定化酶载体及生化分离材料。     

玻璃微珠填充PBT/GF复合材料的加工和力学性能

研究了玻璃微珠（GB）用量对聚对苯二甲酸丁二醇酯（PBT）／短玻纤（GF）复合材料熔体流变性和力学性能的影响。结果表明：GB的加入使复合材料的加工流动性增加，添加1．25份GB时，复合材料的MFR比未添加时增加了21％；随着GB用量的增加，复合材料的拉伸、弯曲强度均减小，而材料的断裂伸长率、冲击强度先增大后减小；添加0．25份GB时复合材料的断裂伸长率和冲击强度分别比未添加时增加了11％和33％。     

Ceramic microspheres with controlled porosity by emulsion-ice templating

Silicon Carbide porous microspheres were fabricated using a preceramic polymer by emulsion-ice templating. An oil-in-water macroemulsion was prepared by adding an organic solution, comprising polycarbosilane and cyclohexane, to the aqueous phase containing a nonionic surfactant. Upon directional freezing and freeze drying, microspheres with aligned pores were obtained. The influence of processing parameters was assessed. In particular, the solidification temperature affected size and morphology of the macroporosity. Our strategy enables an independent control of macro and nanoporosity. Indeed, the thermal treatment can be optimized to tune the micro-porosity at the nanoscale as well as the specific surface area of the samples.The emulsion-ice templating technique was optimized to produce microspheres with multimodal macroporosity up to 90 vol.% in the range 1–30 μm, with micro- and meso-pores with diameter up to 6 nm, and specific surface area as high as 117 m² g⁻¹.     

Tailoring thermoresponsive microbeads in supercritical carbon dioxide for biomedical applications

The preparation of smart polymeric particles in supercritical carbon dioxide (scCO₂) presents many advantages for biomedical applications over conventional processes due to the easy elimination of trace contaminants rendering highly pure particles. Herein we report the successful optimization of poly(N-isopropylacrylamide) (PNIPAAm) synthesis strategy to obtain cell-sized hydrogel microbeads with defined and systematically varied mechanical properties. The effect of using different hydrophilic cross-linkers such as N,N-methylenebisacrylamide (MBAm), di(ethylene) glycol dimethacrylate (DEGDMA) and glycerol dimethacrylate (GDMA), on beads morphological, physico-chemical and mechanical properties was investigated. In agreement with a larger water uptake ability beads cross-linked with DEGDMA are more compliant than those containing MBAm or GDMA, having lower stiffness as accessed through oscillatory measurements on a rotational rheometer. Cytotoxicity assays showed that the obtained cross-linked PNIPAAm microbeads do not present any toxic effect on fibroblast cell cultures. Microbeads biocompatibility and adequate mechanical compliance enable their potential application on biomedical settings.     

特高折射率玻璃微珠的制备及折射率测量方法

采用高温吹制工艺制备出直径３０～５５μｍ、特高折射率玻璃微珠。以近轴光线成像的理论为基础，提出了用光学显微镜测量玻璃微珠折射率的简便方法。测得所制备玻璃微珠的平均折射率为２．４７；分析和讨论了测量方法的误差和实用性。     

Membrane emulsification for the production of uniform poly-N-isopropylacrylamide-coated alginate particles using internal gelation

Alginate particles, crosslinked by calcium ions, have a number of potential biopharmaceutical industry applications due to the biocompatibility of the materials used and formed. One such use is as microcarriers for cell attachment, growth and then detachment without the use of proteolytic enzymes. A straightforward and reproducible method for producing uniform calcium alginate particles with controllable median diameters which employs membrane emulsification and internal gelation (solid particles contained in the dispersed phase) is demonstrated, as well as functionalisation of the resulting beads with amine terminated poly N-isopropylacrylamide (pNIPAM) to form temperature responsive particles, by taking advantage of the electrostatic interaction between the carboxyl groups of the alginate and amino groups of the modified pNIPAM. Cell attachment, growth and detachment capabilities of these core–shell structures were assessed and successfully demonstrated by using phase contrast microscopy and fluorescent staining with calcein-AM and ethidium homodimer-1.