皮下注射胰岛素是控制血糖水平最有效的方法,在1型和晚期2型糖尿病患者的治疗中起着至关重要的作用。然而频繁的皮下注射给患者带来了极大的痛苦,因此,针对糖尿病的治疗,目前更倾向采用口服疗法。口服胰岛素可以模拟生理胰岛素的分泌,...皮下注射胰岛素是控制血糖水平最有效的方法,在1型和晚期2型糖尿病患者的治疗中起着至关重要的作用。然而频繁的皮下注射给患者带来了极大的痛苦,因此,针对糖尿病的治疗,目前更倾向采用口服疗法。口服胰岛素可以模拟生理胰岛素的分泌,并对肝脏葡萄糖代谢提供更全面的调节,但胃肠道的吸收不良极大地阻碍了胰岛素口服给药的发展。纳米药物递送系统(nanoscale drug delivery systems,NDDS)的快速发展增加了胰岛素口服给药的可能性。高分子纳米材料是NDDS中一类重要的载体材料,已被广泛用于促进胰岛素口服吸收的研究。它具有生物降解性、生物相容性和储存稳定性等优点,并且其分子链长易于改性、修饰和加工成型。高分子纳米材料可以保护包裹的胰岛素不受酸性变性和酶降解的影响,促进细胞对胰岛素的摄取,从而提高胰岛素的生物利用度。讨论了口服胰岛素的主要生理障碍,总结了近几年用于口服胰岛素递送的高分子纳米材料的研究进展。展开更多
The diffusion of nanoparticles immersed in semidilute polymer solutions is investigated by a hybrid mesoscopic multiparticle collision dynamics method. Effects of polymer concentration and hydrodynamic interactions am...The diffusion of nanoparticles immersed in semidilute polymer solutions is investigated by a hybrid mesoscopic multiparticle collision dynamics method. Effects of polymer concentration and hydrodynamic interactions among polymer monomers are focused. Extensive simulations show that the dependence of diffusion coefficient D on the polymer concentration c agrees with Phillies equation D-exp （-αc^δ） with a scaling exponent δ≈0.97 which coincides with the experimental one in literature. For increasing nanoparticle size, the scaling prefactor α increases monotonically while the scaling exponent always keeps fixed. Moreover, we also study the diffusion of nanoparticle without hydrodynamic interactions and find that mobility of the nanoparticle slows down, and the scaling exponent is obviously different from the one in experiments, implying that hydrodynamic interactions play a crucial role in the diffusion of a nanoparticle in semidilute polymer solutions.展开更多
Fast crystallization of nanosized zeolite crystals is a very popular process used for practical zeolite catalyst applications. Herein, we report a designer crystallization process for nanosized zeolite omega crystals ...Fast crystallization of nanosized zeolite crystals is a very popular process used for practical zeolite catalyst applications. Herein, we report a designer crystallization process for nanosized zeolite omega crystals based on the relationship between the crystallization time and temperature in the Arrhenius equation. Compared to the conventional hydrothermal synthesis of zeolite omega(72 h at room temperature and 240 h at 100℃, MAZ-100), the crystallization of zeolite omega presented in this work only requires a very short time interval(5 h at 180℃, MAZ-180). Physicochemical characterizations, including XRD, SEM, N2 sorption isotherms, and 27 Al MAS NMR show that the product of zeolite omega(MAZ-180) has good crystallinity and uniform nanocrystals. More importantly, after the loading of Pt nanoparticles(0.5 wt%), the Pt/H-MAZ-180 catalyst exhibits higher isomer selectivity and lower cracking selectivity than those of the Pt/H-MAZ-100 catalyst in the hydroisomerization of n-dodecane. These results suggest the potential applications of these omega nanocrystals as supporting catalyst compounds in industrial processes.展开更多
Biodegradable polymeric nanoparticles are more and more frequently used in drug delivery systems, which represent one of the most rapidly developing areas. In our previous study, a novel natural hybrid polyester, poly...Biodegradable polymeric nanoparticles are more and more frequently used in drug delivery systems, which represent one of the most rapidly developing areas. In our previous study, a novel natural hybrid polyester, polyethylene glycol 200 （PEG200） end-capped poly （3-hydroxybutyrate-co-3-hydroxyhcxanoate） （PHBHHx-PEG） was directly produced by Aeromonas hydrophila fermentation. In this study, the performance of the novel biodegradable PHBHHx-PEG copolyester as a sustained release carrier for hydrophobic drugs with different molecular weights and the in vitro sustained release profile were investigated. 5-Fluorouracil （5-Fu, Mw=130.1）, TGX221 （Mw=364.4）, and Rapamycin （RAP, Mw=914.2） were used as the model drugs. PHBHHx-PEG nanoparticles entrapped with 5-Fu, TGX221 and RAP were fabricated by a modified emulsification/solvent evaporation method, respectively. The average diameter of 5-Fu, TGX221, and RAP loaded PHBHHx-PEG nanoparticles was between 198.2-217.4 nm, and the entrapment efficiency of the three drugs was 62.5%, 93.4% and 91.9%, respectively. The in vitro release profiles of 5-Fu, TGX221 and RAP from PHBHHx-PEG nanoparticles were different. 5-Fu showed faster release rate and an obvious initial burst release phase. TGX221 and RAP were demonstrated to be released more slowly and steadily. The release percentages of 5-Fu, TGX221 and RAP were 97.7%, 85.1% and 74.7% after releasing for 72 h. PHBHHx-PEG is a kind of promising material as a carrier for the entrapment and delivery of hydrophobic drugs especially for those drugs with high molecular weight.展开更多
文摘皮下注射胰岛素是控制血糖水平最有效的方法,在1型和晚期2型糖尿病患者的治疗中起着至关重要的作用。然而频繁的皮下注射给患者带来了极大的痛苦,因此,针对糖尿病的治疗,目前更倾向采用口服疗法。口服胰岛素可以模拟生理胰岛素的分泌,并对肝脏葡萄糖代谢提供更全面的调节,但胃肠道的吸收不良极大地阻碍了胰岛素口服给药的发展。纳米药物递送系统(nanoscale drug delivery systems,NDDS)的快速发展增加了胰岛素口服给药的可能性。高分子纳米材料是NDDS中一类重要的载体材料,已被广泛用于促进胰岛素口服吸收的研究。它具有生物降解性、生物相容性和储存稳定性等优点,并且其分子链长易于改性、修饰和加工成型。高分子纳米材料可以保护包裹的胰岛素不受酸性变性和酶降解的影响,促进细胞对胰岛素的摄取,从而提高胰岛素的生物利用度。讨论了口服胰岛素的主要生理障碍,总结了近几年用于口服胰岛素递送的高分子纳米材料的研究进展。
文摘The diffusion of nanoparticles immersed in semidilute polymer solutions is investigated by a hybrid mesoscopic multiparticle collision dynamics method. Effects of polymer concentration and hydrodynamic interactions among polymer monomers are focused. Extensive simulations show that the dependence of diffusion coefficient D on the polymer concentration c agrees with Phillies equation D-exp （-αc^δ） with a scaling exponent δ≈0.97 which coincides with the experimental one in literature. For increasing nanoparticle size, the scaling prefactor α increases monotonically while the scaling exponent always keeps fixed. Moreover, we also study the diffusion of nanoparticle without hydrodynamic interactions and find that mobility of the nanoparticle slows down, and the scaling exponent is obviously different from the one in experiments, implying that hydrodynamic interactions play a crucial role in the diffusion of a nanoparticle in semidilute polymer solutions.
基金supported by the National Natural Science Foundation of China(91545111,91634201,21720102001)National Key Research and Development Program of China(2017YFB0702803)Shell Foundation~~
文摘Fast crystallization of nanosized zeolite crystals is a very popular process used for practical zeolite catalyst applications. Herein, we report a designer crystallization process for nanosized zeolite omega crystals based on the relationship between the crystallization time and temperature in the Arrhenius equation. Compared to the conventional hydrothermal synthesis of zeolite omega(72 h at room temperature and 240 h at 100℃, MAZ-100), the crystallization of zeolite omega presented in this work only requires a very short time interval(5 h at 180℃, MAZ-180). Physicochemical characterizations, including XRD, SEM, N2 sorption isotherms, and 27 Al MAS NMR show that the product of zeolite omega(MAZ-180) has good crystallinity and uniform nanocrystals. More importantly, after the loading of Pt nanoparticles(0.5 wt%), the Pt/H-MAZ-180 catalyst exhibits higher isomer selectivity and lower cracking selectivity than those of the Pt/H-MAZ-100 catalyst in the hydroisomerization of n-dodecane. These results suggest the potential applications of these omega nanocrystals as supporting catalyst compounds in industrial processes.
基金National Natural Science Foundation of Chinagrant number:81172170,81371288+1 种基金Science and Technology Research and Development Program of Shanxi Provincegrant number:2013KW32-04
文摘Biodegradable polymeric nanoparticles are more and more frequently used in drug delivery systems, which represent one of the most rapidly developing areas. In our previous study, a novel natural hybrid polyester, polyethylene glycol 200 （PEG200） end-capped poly （3-hydroxybutyrate-co-3-hydroxyhcxanoate） （PHBHHx-PEG） was directly produced by Aeromonas hydrophila fermentation. In this study, the performance of the novel biodegradable PHBHHx-PEG copolyester as a sustained release carrier for hydrophobic drugs with different molecular weights and the in vitro sustained release profile were investigated. 5-Fluorouracil （5-Fu, Mw=130.1）, TGX221 （Mw=364.4）, and Rapamycin （RAP, Mw=914.2） were used as the model drugs. PHBHHx-PEG nanoparticles entrapped with 5-Fu, TGX221 and RAP were fabricated by a modified emulsification/solvent evaporation method, respectively. The average diameter of 5-Fu, TGX221, and RAP loaded PHBHHx-PEG nanoparticles was between 198.2-217.4 nm, and the entrapment efficiency of the three drugs was 62.5%, 93.4% and 91.9%, respectively. The in vitro release profiles of 5-Fu, TGX221 and RAP from PHBHHx-PEG nanoparticles were different. 5-Fu showed faster release rate and an obvious initial burst release phase. TGX221 and RAP were demonstrated to be released more slowly and steadily. The release percentages of 5-Fu, TGX221 and RAP were 97.7%, 85.1% and 74.7% after releasing for 72 h. PHBHHx-PEG is a kind of promising material as a carrier for the entrapment and delivery of hydrophobic drugs especially for those drugs with high molecular weight.
