| Glioblastoma multiforme (GBM) is the most aggressive brain tumor in humans. The morbidity accounted for about40%in the central nervous system tumors,78%in the adult neural malignant tumor[1].After30years of development,although neuroimaging and the treatment of gliomas have made great progress,the prognosis of malignant glioma is still not well.The survival rate of adult glioblastoma in1year and5years is about30%and13%respectively.Median survival for patients with GBMs is only12months[2].Gene therapy provide a new hope for multimodal treatment,but it has been severely restricted by the limited distribution of vectors within tumors. Gene therapy could completely conquer cancer in theory, bring great hope for the cure.But the naked therapeutic genes can’t effectively get through the blood brain barrier, for the lack of efficient and stable carrier system, leading to its treatment efficiency is not well.This experiment by two-step sol-gel method, gelatin-siloxane nanoparticles (GS NPs) was synthesized.On this base, we build a nanoparticles gene carrier systems were modified by the hydrophilic polyethylene glycol (PEG), cationic peptides Tat, nucleic acid adaptation TTA1and Fe3O4. It can not only get through the blood brain barrier, targeted brain tumor cells, but also get MRI enhancement effect. To investigate its transfection efficiency at a cellular level by carrying plasmid DNA, to provide theoretical and practical support for the application of nanoparticles as a transport carrier.At the first part,we represent the characterization of GS NPs with Fe3O4coupling by the fourier transform infrared spectroscopy (FT-IR).By the analysis of the surface potential of nanoparticles (Zeta potential), nanometer particle size analysis (DLS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), and other physical and chemical analysis method, we study the physical and chemical properties of the material. At the second part, through the laser confocal microscopy, MRI and other imaging techniques, to verify the imagine that the GS NP-Fe3O4as gene carrier can be effectively absorbed by C6cells, and can target efficiency expression in tumor cells with carrying the GFP (green fluorescent protein) reporter gene. By magnetic resonance imaging to scan for T2weighted sequence and its relaxation rate is measured r2value in the certain concentration range after cell co-culture of GS NP-Fe3O4and Fe3O4, for verifying the possibility of GS NP-Fe3O4as MRI contrast agent.At the third part, through the method of brain stereotaxic instrument injections of C6glioma cells,we establish the rat glioma model. By tail vein injection of GS NPs-Fe3O4and Fe3O4respectively, compare different MRI imaging effect between those nanoparticles, observed the signal changes. The tumor specimen sections of HE and Prussian blue staining,can inspects its pathological changes. By the slices of rat C6glioma and MRI imaging detection,to explore whether GS NPs-Fe3O4specificity target imaging features,as well as the transfection efficiency to the glioma and the carrier of drug delivery systems in the brain broad application prospects, which can take a huge advantage in tumor diagnosis, drug delivery and targeting therapy. |
PDF Full Text Request