可降解自乳化聚氨酯微球的合成及性能研究

将预聚-扩链-中和-乳化法联合运用,一步合成出自乳化聚氨酯微球。研究了自乳化聚氨酯微球的合成条件。包括二异氰酸酯单体种类对微球形态的影响;异佛尔酮二异氰酸酯（IPDI）和聚丙二醇（PPG）单体配比对乳化效果的影响;乳化时间对微球形态的影响;反应温度、聚合时间和搅拌速度等对微球合成的影响。并以可降解的聚乳酸（PLA）取代部分PPG合成出可降解的自乳化聚氨酯微球,对其在磷酸缓冲液中的降解性进行了研究。通过IR及SEM对自乳化聚氨酯微球进行了表征,找出了合成稳定、均匀和形态好的自乳化聚氨酯微球的最佳条件。     

乳液聚合法合成聚苯乙烯高分子微球及表征

采用乳液聚合法合成高分子微球具有方法简单条件易控等特点,采用乳液聚合法合成了纳米级的聚苯乙烯高分子微球,研究了不同聚合条件下聚苯乙烯高分子微球的表征,结果表明,聚合温度、乳化剂用量、搅拌速度对聚苯乙烯高分子微球的平均分子量、粒径有显著影响。     

淀粉微球的用途及发展建议

介绍了淀粉微球的合成原理、特点、用途、合成方法,指出:提高淀粉靶向性,降低微球粒径及降低成本以便工业化是未来发展方向,淀粉微球较一般交联淀粉发展前景广阔。     

单分散SiO2微球的合成及胶体晶体的生长

对传统的"Stober-Fink"合成SiO2微球的工艺进行了改进,运用"籽晶生长法"合成了单分散SiO2微球,该法可以准确地控制微球尺寸,提高微球的球形度.采用垂直沉积法制备了胶体晶体,并对样品的结构和光学性能进行了表征.研究了微球尺寸对垂直沉积SiO2胶体晶体光子带隙的影响,结果表明,通过控制微球粒径,可调节光子晶体的带隙位置.     

Pickering细乳液法制备无机聚合物复合中空微球

采用有机胺催化水解正硅酸乙酯生成SiO_2纳米粒子,经硅烷偶联剂改性后,获得了两亲性的SiO_2纳米粒子。以其作为Pickering乳化剂,成功制备了稳定的Pickering细乳液并合成了无机聚合物复合中空微球。通过红外光谱、透射电镜、扫描电镜和热重分析等测试手段对复合中空微球进行了表征。结果表明:引发剂为偶氮二异庚腈、交联剂用量为0.2%时合成了直径在1.5~2μm之间的复合中空微球。采用低温引发剂有利于合成均一粒径的中空微球;交联剂的用量能够改变微球的粒径大小;不同的单体类型会影响微球的粒径分布。     

PNIPAAm接枝PAN/PSt热敏性聚合物微球的制备

用链转移自由基聚合和端基置换反应,合成了聚N-异丙基丙烯酰胺（PNIPAAm）热敏性大分子单体。以此为反应性分散稳定荆,在与丙烯腈／苯乙烯进行的三元分散共聚合中,一步合成了PNIPAAm接枝聚丙烯腈／聚苯乙烯聚合物微球。用透射电子显微镜（TEM）和激光光散射（LLS）对微球进行了表征,实验结果表明：合成得到的聚合物微球其粒径均一、分散稳定性好,并具有明显的热敏性特征,为一类新型聚合物微球。     

新型聚氨酯微球的合成及其形态研究

通过自乳化的方法合成了具有聚己内酯-聚乙二醇-聚己内酯嵌段结构的聚氨酯水溶液,再采用凝聚相分离法合成了一种新型的聚氨酯微球.研究了聚乙二醇分子量、异氰酸基与羟基的摩尔比、聚己内酯与聚乙二醇的摩尔比、预聚温度、聚氨酯水溶液浓度、CaCl2浓度和搅拌速度等条件对聚氨酯微球的影响,以及傅立叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)表征了微球的化学结构和表面形态结构.通过对合成条件的优化,找出了合成稳定、均匀和形态好的聚氨酯微球的最佳条件.实验结果表明,制备的聚氨酯微球平均粒径2mm左右,分布相对均匀,球形较好.     

微米级单分散聚苯乙烯微球的制备

用分散聚合法合成2～6μm单分散好的聚苯乙烯微球,分别考察单体、稳定剂的两步加料方式,以及初始单体浓度、引发剂用量、反应温度等对所合成的聚合物微球粒径及粒径分布的影响。结果表明:两步加料方式可以显著改善微球的单分散性;随着初始单体浓度、引发剂用量增加和反应温度的升高,最终得到的聚苯乙烯微球粒径虽有所增加,但微球粒径分布变宽。将反应液体积放大、单次合成聚苯乙烯微球量不低于250g时制备出的2～6μm系列的聚苯乙烯微球,用扫描电镜等进行表征可知,所制备的聚苯乙烯微球球形度均大于0.95,相对标准偏差均小于5%。     

磁性载药微球的制备

合成了含有铁粉和抗癌药的明胶微球,这种微球在体外磁场的作用下具有定位作用。微球的粒径在０２～１３ｍｍ之间,粒径大小是由制备条件决定的。微球可用戊二醛进行固化。研究了微球体外药物的释放规律     

不同形貌的TiO_2微球可控合成与机理研究

在盐酸溶液体系中,以TiCl4为原料,采用水热法制备分形结构金红石TiO_2微球。通过对水热温度、反应物配比、加入NaCl等水热条件的考察,讨论了不同水热条件对TiO_2晶型和形貌的影响。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对不同形貌的TiO_2微球样品进行表征。SEM分析表明水热合成TiO_2微球的形貌和大小可控,XRD表明合成的TiO_2微球均为金红石型,最后提出了金红石型TiO_2微球的合成机理。     

壳聚糖微球的季铵化及其抗菌性能的研究

采用乳化交联法制备了壳聚糖微球,并对其进行季铵化表面改性。实验分别考察了溶剂、反应时间和季铵化试剂C_4H_9Br与壳聚糖微球物质的量之比对季铵化壳聚糖微球的影响。研究结果表明,壳聚糖微球在乙腈溶液中分散较好,反应时间为12h,季铵化试剂与壳聚糖微球的物质的量之比为3∶1时,制备的季铵化壳聚糖微球效果较好。对壳聚糖、壳聚糖微球、季铵化壳聚糖微球进行抗菌性能测试,发现其抗菌性能的强度大小依次为:季铵化壳聚糖>壳聚糖微球>壳聚糖,其中季铵化壳聚糖微球的抑菌率为52.1%。     

汽巴蓝功能微球对人血清白蛋白的吸附性能研究

通过分散共聚制得了聚苯乙烯接枝聚醋酸乙烯酯(PSt-g-PVAc)微球,粒径控制在500～700nm之间.在碱性条件下将PSt-g-PVAc微球表面的PVAc链醇解为聚乙烯醇(PVA),得到了PSt-g-PVA微球,提高了其在水中的分散稳定性.使汽巴蓝(CB)与PSt-g-PVA表面的羟基进行亲核反应,制得了CB作为配体的新型吸附剂汽巴蓝功能微球(CB微球),元素分析测得CB微球表面的CB最大含量为139.22μmol/g,探讨了其在不同人血清白蛋白(HSA)浓度、pH值和吸附时间下对HSA的吸附性能.当HSA浓度为1.0mg/mL、pH为5.14时,CB微球对HSA的最大吸附量为40.9mg/g,并分析了CB微球与HSA的相互作用机理.由NaSCN进行解吸试验,发现可将吸附在CB微球上的HSA解吸92.11%以上,且CB微球的重复使用性能良好.     

Preparation and characterization of ketoprofen-loaded microspheres for embolization

To deliver drug locally and relieve the syndrome of pain after uterine artery embolization, N-[tris (hydroxymethyl) methyl] acrylamide-gelatin microspheres were prepared based on inverse suspension polymerization and then separated into a number of subgroups (150–350, 350–560, 560–710, 710–1,000, and 1,000–1,430 μm) by wet-sieving. The microspheres were dried by lyophilization or by washing with anhydrous ethanol. And ketoprofen was loaded by soaking dried blank microspheres into concentrated ketoprofen ethanol solution. The ketoprofen loading level in different subgroups of microspheres was measured and found higher when the microspheres were dried by lyophilization. Equilibrium water content and mean diameters of microspheres decreased after drug loading, especially in subgroups with larger size. The microspheres went through the catheter without any difficulty. Compression and relaxation tests were performed on microspheres before lyophilization, embosphere™, microspheres after lyophilization and ketoprofen loading microspheres. The Young’s moduli were 54.74, 64.19, 98.15, and 120.44 kPa, respectively. The release of ketoprofen from microspheres in different subgroups was studied by using the USPII method and T-cell apparatus, respectively. The results indicate that the release rate of ketoprofen depends upon the diameter of microspheres, the type of dissolution apparatus and the flow rate of media in the case that T-cell apparatus was applied. The CH50 test shows that the activation of complement by ketoprofen-loaded microspheres was lower than by blank ones.     

A novel solid-stabilized emulsion approach to CuO nanostructured microspheres

Nanostructured CuO microspheres were prepared by a novel solid-stabilized emulsion for the first time. SEM, TEM, XRD, size analysis and BET measurement were used to characterize the CuO microspheres. The average diameter of the CuO microspheres was 2.8 μm. The surfaces of the CuO microspheres were made of pin-like nanostructures with a pin diameter of 95 nm and a pin length of at least 600 nm. The XRD analysis indicated that the CuO nanostructured microspheres were of monoclinic lattice. The specific surface area of the CuO nanostructured microspheres was about 56.8 m²/g. A mechanism for the formation of the CuO microspheres with nanostructured surfaces was proposed.     

MgO nanostructured microspheres synthesized by an interfacial reaction in a solid-stabilized emulsion

Nanostructured MgO microspheres were prepared by a novel solid-stabilized emulsion for the first time. SEM, XRD, size analysis and BET measurement were used to characterize the MgO microspheres. The diameter of the MgO microspheres was in a range of 5.1 to 5.4 μm. The surfaces of the MgO microspheres were made of leaf-like nanostructures with a leaf thickness of 65 nm. The XRD analysis indicated that the MgO nanostructured microspheres were of cubic lattice. The specific surface area of the MgO nanostructured microspheres was about 105.8 m²/g. The MgO microspheres with nanostructured surfaces had a larger specific surface area than the MgO polyhedral particles prepared by the comparing experiment (via a conventional homogeneous precipitation route). An interfacial reaction mechanism for the formation of the MgO microspheres with nanostructured surfaces was proposed.     

Preparation of alginate microspheres by water-in-oil emulsion method for drug delivery: Effect of Ca2+ post-cross-linking

Alginate microspheres were prepared by a water-in-oil emulsion solvent diffusion method. The alginate microspheres were post-cross-linked with Ca²⁺ ions. Influence of Ca²⁺ concentration on the characteristics and drug release behaviors of alginate microspheres was evaluated. Blue dextran was used as a water-soluble model drug. The non-cross-linked alginate microspheres were less than 100 μm in size and had a spherical shape. The cross-linked alginate microspheres were also spherical in shape with a rougher surface but their particle sizes were larger than 100 μm. The drug encapsulation efficiency of the non-cross-linked alginate microspheres was very high (82%). The drug encapsulation efficiency of alginate microspheres cross-linked with 5% and 10% Ca²⁺ concentrations were similar to the non-cross-linked microspheres. The in vitro drug releases of the cross-linked alginate microspheres showed prolong release profiles. The cumulative release of blue dextran decreased as the Ca²⁺ concentration increased. Thus, Ca²⁺-post-cross-linked alginate microspheres show possibility for use as controlled-release drug carriers.     

Preparation of poly (l-lactic acid) microspheres by droplet-freezing process

A recently developed process of microsphere preparation, named droplet-freezing process is introduced in this paper. The PLLA microspheres were fabricated by the droplet-freezing process, the diameter and porosity of the microspheres were measured, and the micro-morphologies of the microspheres were characterized by scanning electron microscopy (SEM). The formation process of microspheres was achieved by two steps: first, after droplets dropped off the delivery tube, they became approximately spherical in the air under the effect of the surface tension; second, droplets dropped into liquid condensate and maintained the spherical shape, and were frozen during the free settling process. Experimental results indicated that the microspheres fabricated by the droplet-freezing process have uniform diameters and the diameter can be controlled properly, along with the increase of the PLLA concentration, the size of microspheres increases, but the porosity of the microspheres decreases. The microspheres with high porosity can be obtained with a low concentration of the PLLA solution. SEM analysis revealed that the surfaces and interiors of the microsphere contain plentiful and interconnected micro pores. The microspheres are hopeful to be applied in bone tissue engineering.     

非均相悬浮法制备多孔羟基磷灰石微球

为了获得具有吸附和生物学功能的多孔羟基磷灰石(HA)微球,以自制的纳米羟基磷灰石(HA)粉体为原料,用非均相悬浮法制备了HA/明胶微球,将微球在1 250℃下焙烧,成功制备了直径100~500μm的多孔HA微球.采用光学显微镜、SEM分析、XRD分析和BET氮吸附法研究了微球形貌、尺寸、物相组成、比表面积和孔径,测定了微球对水中F-离子的吸附性能.结果表明:微球具有良好球形形貌和相互贯通的纳米微孔;尺寸比较均匀,分散性良好;微球的主要结晶相为羟基磷灰石;BET表面积为1.867 0~2.089 5 m~2/g,孔径6.53~6.85 nm;对氟离子的平衡吸附容量为1.909~1.940 mg/g.通过控制m(HA)/m(明胶)比例、油温、搅拌速度和搅拌时间,可以在一定范围内控制微球直径和比表面积.     

磁性高分子微球研究进展

对磁性高分子微球的研究进展进行了综述，介绍了各类微球的制备方法及相关原理。在此基础上，概述了磁性高分子微球在磁性塑料、固定化酶、细胞分离和靶向药物等领域的应用情况，并对磁性高分子微球的未来研究方向进行了展望。