ABSTRACT
Novel solid lipid nanoparticle (SLN) system is prepared with Compritol ATO 888 and tricaprylic glyceride. DSC, XRD, SAXS and NMR are employed to study the novel carrier property and microstructure. When the peak melting point decreased from 70.8 degrees C to 61.4 degrees C, the enthalpy sharply decreased. It could be concluded that the regular crystal lattices in the novel carriers are broken out for the oil joined in them. Melting behavior is occurred at -17.7 degrees C while novel SLN is composed of oil and solid lipid mixture from the DSC measurement. Most alpha phase and least beta' phase are in the nano carrier system whether drug loading or not from the XRD investigation. There is only 0.1 nm change of long space among the novel SLN made of mixture and the lipid matrix and traditional SLN; therefore, it is impossible of the oil molecular insert into the solid glyceride structure. Since the different melting behavior (DSC measurements) and molecular move state (NMR investigations), two lipid matrix are still in two state of liquid and solid lipid in the novel SLN carrier. Presume the microstructure of the novel SLN prepared by our experiment would be that liquid oil has formed superfine nano accommodation encapsulated with solid lipid, but the whole particle is still in nano size range.
Subject(s)
Calorimetry, Differential Scanning , Caprylates , Chemistry , Diterpenes , Chemistry , Drug Carriers , Chemistry , Drug Delivery Systems , Epoxy Compounds , Chemistry , Fatty Acids , Chemistry , Magnetic Resonance Spectroscopy , Nanoparticles , Particle Size , Phenanthrenes , Chemistry , Triglycerides , Chemistry , X-Ray DiffractionABSTRACT
<p><b>OBJECTIVE</b>To investigate a new strategy of polylactic acid (PLA) nanoparticles delivery system coating nuclear factor-kappaB (NF-kappaB) decoy oligonucleotides (ODNs) for inhibiting TF expression in cultured brain microvascular endothelial cells(BMECs).</p><p><b>METHODS</b>PLA nanoparticles coating FITC-labeled NF-kappaB decoy ODNs were formulated by nano-deposition method and the characteristics of nanoparticles were detected. BMECs were isolated and cultured in vitro. The cellular uptake and intracellular localization of nanoparticles in BMECs was detected by flow cytometry and confocal microscopy. Changes in the expressions of TF and nuclear protein P65 were examined by RT-PCR and Western blot in NF-kappaB decoy ODNs transfected BMECs by LPS stimulation.</p><p><b>RESULTS</b>The decoy-nanoparticles obtained were uniform spherical particles with an effective diameter of 162.1 nm and a polydispersity index of 0.118. NF-kappaB decoy ODNs encapsulated in nanoparticles could be released in a controlled manner in phosphate-buffered saline for up to 28 days. It was observed that the cellular uptake of nanoparticles were increased with the time of incubation and the concentration of nanoparticles in the medium. Nanoparticles localized mainly in the BMECs cytoplasm. LPS-induced upregulation of TF transcription was inhibited by NF-kappaB decoy ODNs transfection but not by missense ODNs transfection. Furthermore, changes in the transcription level of TF were paralleled by a reduction of capacity of P65 in nuclear extract of NF-kappaB decoy ODNs transfected cells.</p><p><b>CONCLUSIONS</b>These findings offer a potential therapeutic strategy in the control of TF expression in BMECs in vitro.</p>
Subject(s)
Animals , Rats , Brain , Capillaries , Cell Biology , Cells, Cultured , Endothelial Cells , Metabolism , Gene Expression Regulation , Lactic Acid , NF-kappa B , Genetics , Nanoparticles , Oligonucleotides , Genetics , Polyesters , Polymers , Thromboplastin , Genetics , Metabolism , TransfectionABSTRACT
The blood-brain barrier (BBB) is a huge obstacle in therapy of brain diseases, for it hinders the delivery of water-soluble molecules and those with molecular weight above 500 from the circulation system to the brain. Polysorbate 80 (Tween 80, T-80)-coated polylactid acid(PLA) nanoparticles represent a tool to transport such drugs across the BBB. Transcytosis is put forward as one mechanism of drug-loaded nanoparticles across the blood-brain barrier (BBB). However little is known about it. Electron microscopy is an important method in the investigation on nanoparticles injected into the experimental mice. In this study it was found by fluorescence microscope that fluorescence existed along the capillary dissepiment. Some nanoparticles distributed in the brain capillary endothelial cells and brain tissue outside the microvaculum, which was observed by transmission electron microscopy. These particles were proved to be the Copper chlorophyll loaded nanoparticles which containing Cu detected by AEM. The in vivo experiments demonstrated directly that the PLA nanoparticles can pass the BBB indeed and transcytosis by microvascular endothelial cells may be the mechanism. The results provided an efficient way of drug-delivery targeting the brain. Copper chlorophyll could be used as a new symbol of nanoparticles in in vivo experiment.