Tat-聚乙二醇修饰明胶-硅氧烷纳米粒跨血脑屏障研究

Research on Tat Peptide-polyethylene Glycol Modified Gelatin-siloxane Nanoparticles Across the Blood-brain Barrier

明胶-硅氧烷杂化材料具有低毒、表面易修饰、易重复合成等优点,并可介导外源基因在细胞内进行高效率转染,是一种潜在的高效基因载体材料。本文通过两步溶胶-凝胶反应合成明胶-硅氧烷纳米粒(GS NPs),经Tat多肽(KYGRRRQRRKKRGC)、聚乙二醇(PEG)表面修饰构成Tat-PEG-GS NPs。应用透射电镜(TEM)、粒径仪和活体成像系统对其粒径、形貌、zeta电位、跨血脑屏障入脑能力进行评价。结果得出,Tat-PEG-GS NPs粒径分布在150～200nm、zeta电位(32.27±2.47)mV;TEM观察显示Tat-PEG-GS NPs可跨过血脑屏障到达脑组织,活体成像显示Tat-PEG-GS NPs较PEG-GS NPs在脑部的荧光强,Tat-PEG-GS NPs比PEG-GS NPs在肝脏、脾脏的荧光低,差异具有统计学意义。证明Tat-PEG-GS NPs可以逃逸内皮网状吞噬系统的吞噬,跨过血脑屏障到达脑实质内,是一种有潜力的入脑纳米载体系统。

Gelatin-siloxane nanoparticles （GS NPs） have been considered to be good gene carrier candidate in vitro, since they have several advantages such as low toxicity, easy preparation and surface modification. In this study, the Tat-PEG-GS NPs were synthesized by the gelatin-siloxane, surface-modified with the polyethylene glycol （H2N- PEG-COOH） and Tat peptide （KYGRRRQRRKKRGC） and thus constructed a delivery system which can cross BBB （Blood-brain barrier）. The morphology, diameter, and zeta potential of Tat-PEG-GS NPs carrier system were characterized with transmission electron microscopy （TEM） and Nano-ZS zetasizer dynamic light scattering Detector. The organ distribution and dynamic evolution localized in the brain parenchyma of Tat-PEG-GS NPs in vivo was in- vestigated with Cri in vivo imaging system and TEM. The obtained Tat-PEG-GS NPs were approximately spherical in shape with average particle size of 150-200 nm and zeta potentials of （32.27±2.47） mV. In vivo imaging results showed that the accumulation of Tat-PEG-GS NPs was higher in the brain than the accumulation of PEG-GS NPs, but the accumulation of Tat-PEG-GS NPs was lower in the liver than the accumulation of PEG-GS NPs. These differences are statistically significant. The nanocomplex could cross the BBB and reach the neural tissues tested with TEM. The Tat-PEG-GS NPs could cross the BBB and escape the arrest of the reticuloendothelial system （RES）, and it would be potential nano-carrier systems for central delivery.