Delivery of diagnostic or therapeutic agents across the blood-brain barrier (BBB) remains a major challenge of brain disease treatment. Magnetic nanoparticles are actively being developed as drug carriers due to magnetic targeting and subsequently reduced off-target effects. In this paper, we developed a magnetic SiO2@Fe3O4 nanoparticle-based carrier bound to cell-penetrating peptide Tat (SiO2@Fe3O4
-Tat) and studied its fates in accessing BBB. SiO2@Fe3O4-Tat nanoparticles (NPs) exhibited suitable magnetism and good biocompatibility. NPs adding to the apical chamber of in vitro BBB model were found in the U251 glioma cells co-cultured at the bottom of the Transwell, indicating that particles passed through the barrier and taken up by glioma cells. Moreover, the synergistic effects of Tat and magnetic field could promote the efficient cellular internalization and the permeability across the barrier. Besides, functionalization with Tat peptide allowed particles to locate into the nucleus of U251 cells than the non-conjugated NPs. These results suggest that SiO2@Fe3O4-Tat NPs could penetrate the BBB through the transcytosis of brain endothelial cells and magnetically mediated dragging. Therefore, SiO2@Fe3O4-Tat NPs could be exploited as a potential drug delivery system for chemotherapy and gene therapy of brain disease.
A near-infrared (NIR)-responsive Aurod@pNIPAAm-PEGMA nanogel was synthesized in two steps, growing a PEGMA monolayer on the surface of gold nanorods (AuNRs), followed by in situ polymerization and cross-linking of N-iso-propylacrylamide (NIPAAm) and poly-(ethylene glycol)-methacrylate (PEGMA). The AuNRs and Aurod@pNIPAAm-PEGMA nanogel were characterized by UV–vis spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy, respectively. The lower critical solution temperature of the Aurod@pNIPAAm-PEGMA nanogel could be tuned by changing the molar ratio of NIPAAm/PEGMA. The NIR-mediated drug release behavior of the Aurod@pNIPAAm-PEGMA nanogel was studied with zinc phthalocyanines (ZnPc4) as a drug model. It was also demonstrated that the loaded ZnPc4 could keep the capability of generating singlet oxygen, and the in vitro study showed a great photodynamic therapy (PDT) effect on Hela cells. It thus indicated the potential of this Aurod@pNIPAAm-PEGMA nanogel for application as a drug carrier in PDT, which might make contributions to oncotherapy.
Extremely small-sized superparamagnetic magnetite nanoparticles of 3Cit). The resulting Cit-coated magnetite nanoparticles exhibited long-term colloidal stability in aqueous media without any surface modification. Regarding the magnetic properties, the nanoparticles were superparamagnetic at room temperature, and might be the potential candidate for MRI contrast agents.
Novel hybrid biomaterial of Tat peptide modified gelatin-siloxane nanoparticles (Tat-GS NPs), with positive surface potential was synthesised through a two-step sol-gel process. The particles were subsequently tested in vitro with HeLa cells by fluorescent activitated cell sorter analysis, confocal laser scanning microscopy, and transmission electron microscopy to determine whether the functionalisation with Tat peptide allowed particles to transfer across the cell membrane and locate in the nucleus. Our current results indicated that the internalisation of Tat-GS NPs in HeLa cells is time-and concentration-dependent. Moreover, Tat-GS NPs could penetrate the nucleus membrane and enter into nucleus. The Tat-GS/pDNA nanocomplexes were formulated with higher encapsulation efficiency, and exhibited efficient transfection in vitro. Tat-GS NPs are thus considered as novel non-viral vectors will be widely used in further study.
The Xishanyao reservoir in Niuquanhu area is a typical low permeability reservoir Diagenesis is very important for the physical property of reservoir. Through analyzed data of cast thin sections and scanning electron microscopy (SEM) data, analyzed the impact of main diagenesis on reservoir properties in Niuquanhu area. First, quantitative analyzed the various types of diagenesis on reservoir porosity contribution rate. Second, through restoring the original porosity, quantitative analyzed the pore evolution of reservoir caused by various types of diagenesis. Realized the quantitative analysis of porosity of each diagenesis stage. The quantitative calculation results agree well with the experimental analysis results, the error is 1.09%~1.51%, which showed the rationality of research method and the research results have certain reliability. The study of diagenesis has important significance for fine evaluation and favorable area prediction of Niuquanhu area reservoir.
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