共查询到18条相似文献，搜索用时 187 毫秒
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目的制备卡铂碳包铁纳米壳聚糖微球,摸索最佳制备方案,检测该微球的各项性状,并与卡铂纯铁纳米壳聚糖微球进行比较.方法以吸附药物的碳包铁纳米磁粉为磁性内核,壳聚糖为基质,卡铂为负载药物,采用反相微乳法制备卡铂碳包铁纳米壳聚糖微球.卡铂纯铁纳米壳聚糖微球的制备方法相似,不同的是以无吸附药物能力的纯铁纳米磁粉为磁性内核.检测和比较两种纳米药物微球的形态、粒径、磁响应性、载药量、包封率和体外释药.结果两种药物微球的球形圆整,平均粒径210nm±26nm,粒径分布150nm-300nm,磁响应性强.碳包铁纳米微球的载药量(11.15±1.03)%,纯铁纳米微球载药量(9.21±1.10)%.碳包铁纳米微球1d、2d、3d、4d的体外释药量分别为60%、74%、84%、92%;纯铁纳米微球1d、2d的释药量分别为81%、91%.结论通过活性碳吸附和物理包裹双重机制载药的卡铂碳包铁纳米壳聚糖微球不但载药量高,而且释药速度平稳.多重机制的有机结合是优化纳米微球性能的有效方法. 相似文献
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采用分散聚合法合成了微米级聚甲基丙烯酸甲酯(PMMA)微球，对影响粒径及其分布的各种因素，如单体、引发剂、稳定剂、分散介质以及反应温度等进行了考察，探讨了分散聚合法制备单分散大粒径微球的机理。研究结果表明：增加单体和引发剂浓度，微球的粒径增大，分散性变宽；增加稳定剂的量，微球的粒径减小，分散性变窄；此外分散介质的极性和反应温度的影响也很明显。通过合理调节各种影响因素可制备理想粒径和粒径分布的PMMA微球。 相似文献
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聚合物微球是近几年发展起来的一种新型的深部调堵技术。为考查YG型聚合物微球在中原油田高温高矿化度油藏中的性能,通过透射电镜显微照相、吸水膨胀实验和岩心驱替实验等对其性能进行了评价。结果表明:YG型聚合物微球粒径为50～200nm,体积微小,内核密度较大,可均匀分散在溶液中,与地层水表现出良好的配伍性;用文留油田回注污水配制的微球溶液在95℃条件下,10天吸水膨胀达40倍以上,具有较好的耐温抗盐性能和吸水膨胀性能。YG型聚合物微球注入中低渗透率岩心,呈现压力上升、微球运移、压力下降的波动过程,具有较好的注入性;对中高渗岩心,封堵能力较差,未溶胀时基本无封堵作用,但随溶胀时间的延长,封堵率逐步增加,10天后封堵率17.14%。YG型聚合物微球对中高渗透率地层应增大微球粒径或采取措施前预调剖工艺。 相似文献
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<正>近年来,国内外对疏水缔合聚丙烯酰胺研究较多,而对疏水缔合羟乙基纤维素的研究较少,试验表明疏水缔合羟乙基纤维素具有良好的溶液性质。本文简单介绍了疏水缔合羟乙基纤维素的研究进展。1引言疏水缔合羟乙基纤维素是一种纤维素衍生物,其具有良好的水溶性、耐盐性、无凝胶点、生物相容性、生物降解性和稳定的化学结构等优良特性。重要的是,它还具有疏水缔合聚合 相似文献
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文章研究了羟乙基纤维素基高吸水性材料的合成及其性能.以过硫酸钾-亚硫酸氧钠为引发荆,N,N-亚甲基双丙烯酰胺为交联剂,采用溶液聚合法合成了聚丙烯酸/羟乙基纤维素吸水树脂.研究了交联剂、引发剂、羟乙基纤维素用量及丙烯酸中和度等因素对吸水树脂吸液率的影响.实验结果表明,最佳反应条件是:羟乙基纤维素质量含量为8%,丙烯酸中和度为60%,交联剂和引发荆质量含量分别为0.2%和0.70%.高吸水性树脂吸蒸馏水和生理盐水分别为556倍和64倍. 相似文献
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本文以中温煤沥青为原料,通过热缩聚法与悬浮法相结合制备中间相碳微球。本文分别探讨了在360℃与380℃下恒温3～5h制备中间相碳微球。采用偏光显微镜对中间相碳微球进行结构分析,采用SEM对中间相碳微球进行形貌分析,采用TGA对所制备的中间相碳微球进行热行为分析。结果表明,提高热聚合温度和延长保温时间使得MCMB的粒径变小,球径分布变宽,球体表面更加光滑,制备的中间相碳微球形貌更好。 相似文献
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本实验研究非诺贝特缓释微球片的制备方法并采用高效液相色谱法测定非诺贝特缓释微球片的溶出度。方法:采用依利特hypersilBDS C18色谱柱(4.6*250*5u),水-甲醇-三乙胺(20∶80:0.01),检测波长为286nm,流速为1.0ml/min。非诺贝特缓释微球片微晶纤维素为辅料时效果最佳;硬度为6.0±0.1kg非诺贝特缓释微球片的溶出度最好。结论:本制剂稳定、可靠,有机体内生物利用度高于普通非诺贝特片。 相似文献
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Photo-crosslinkable gelatin methacrylate (GelMa) microspheres are applicable to deliver cells or drugs in biological or biomedical applications. To fabricate GelMa microdroplets, a flow focusing technique with advantages of size control and rapid production was used in a T-junction microfluidic device. Instability played an important role in promoting microdroplet uniformity. 5 wt. % GelMa prepolymer solution mixed with cells affected cell-induced instability. At low flow rate ratio of GelMa to mineral oil below 0.200, stability was maintained regardless of GelMa concentration (5 and 8 wt. %) and cell presence, which led to uniform microdroplet generation. In contrast, instability at high flow rate ratio above 0.200 was worsened by cell presence and unstable jetting length, resulting in the generation of non-uniform cell-laden microdroplets. Therefore, the effect of cell-induced instability on microdroplet generation was minimized at a low flow rate ratio. 相似文献
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Tiantian Kong Jun Wu Kelvin Wai Kwok Yeung Michael Kai Tsun To �� Liqiu Wang 《Biomicrofluidics》2013,7(4)
We report a facile and robust microfluidic method to fabricate polymeric core-shell microspheres as delivery vehicles for biomedical applications. The characteristics of core-shell microspheres can be precisely and easily tuned by manipulating the microfluidic double emulsion templates. The addition of a shell can significantly improve the versatility as well as functionality of these microspheres as delivery vehicles. We demonstrate that the nature of the shell material plays an important role in the properties of the core-shell delivery vehicles. The release kinetics is significantly influenced by the material of the shell and other characteristics such as the thickness. For example, by adding a poly(lactic-co-glycolic acid) (PLGA) shell to an alginate core, the encapsulation efficiency is enhanced and undesired leakage of hydrophilic actives is prevented. By contrast, adding an alginate shell to PLGA core can lead to a reduction of the initial release rate, thus extending the release period of hydrophobic actives. Microfluidic fabrication enables the generation of precisely controlled core-shell microspheres with a narrow size distribution, which enables the investigation of the relationship between the release kinetics of these microspheres and their characteristics. The approach of using core-shell particles as delivery vehicles creates new opportunities to customize the release kinetics of active ingredients. 相似文献
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We have designed, built, and evaluated a microfluidic device that uses deterministic lateral displacement for size-based separation. The device achieves almost 100% purity and recovery in continuously sorting two, four, and six micrometer microspheres. We have applied this highly efficient device to the purification of fungal (Aspergillus) spores that are spherical (∼4 μm diameter) with a narrow size distribution. Such separation directly from culture using unfiltered A. niger suspensions is difficult due to a high level of debris. The device produces a two to three increase in the ratio of spores to debris as measured by light scatter in a flow cytometer. The procedure is feasible at densities up to 4.4×106 spores∕ml. This is one of the first studies to apply microfluidic techniques to spore separations and has demonstrated that a passive separation system could significantly reduce the amount of debris in a suspension of fungal spores with virtually no loss of spore material. 相似文献
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对烟火类发烟剂的组成、工作原理、生产工艺流程及技术指标等作了简要阐述,并对近年来国内外烟火类发烟剂研究中存在的问题及今后的发展方向进行了探讨与展望。烟火类发烟剂既要满足消防演习等烟雾要求,又要具有较高的仿真性及安全性。 相似文献
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Walter Sinnott-Armstrong 《Ethics and Information Technology》1999,1(2):95-104
Internet stings to catch child molesters raise problems for popular tests of entrapment that focus on causation, initiative, counterfactuals, and subjective predisposition. An objective test of entrapment works better in the context of the Internet. The best form of objective test is determined by consequences of drawing a line at various places. This approach allows some Internet stings but counts other stings as entrapment when they go too far. 相似文献
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该方案通过特制的胶片固定架获取天空亮度作为透射光源，将夹持在固定架中的X光片及CT片的透射图像摄于数码相机并导入微机，储存为在医学领域具有广泛用途的高质量数字图像资料。 相似文献
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I. Rabias H. Pratsinis G. Drossopoulou M. Fardis T. Maris N. Boukos N. Tsotakos D. Kletsas E. Tsilibary G. Papavassiliou 《Biomicrofluidics》2007,1(4)
Ultrasmall superparamagnetic iron oxide nanoparticles coated with gummic acid have been investigated as possible constituents of aqueous ferrofluids for biomedical applications and especially for MRI contrast agent. The structural characteristics and the size of the nanoparticles have been analyzed as well as the magnetic properties. In order to evaluate any possible capabilities as a contrast agent, the relaxation time, T2, of hydrogen protons in the colloidal solutions of nanoparticles have been measured in order to gain information on the relaxation behavior compared to other MRI contrast agents. The in vitro cytotoxicity of the obtained magnetic nanoparticles of iron oxide coated with gummic acid was investigated by two separate methods (MTT and FACS analysis) and by using three different normal and transformed cell lines. Our results showed that the synthesized nanoparticles had no toxic effect on any of the cell lines used. 相似文献