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Preparation Of VEGFR-2Targeted And5-Fluorouracil Loaded PLGA Ultrasound Contrast Agent And In Vitro Experimental Study

Posted on:2014-01-24Degree:MasterType:Thesis
Country:ChinaCandidate:J Y ZhangFull Text:PDF
GTID:2254330392966787Subject:Medical imaging and nuclear medicine
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Liver cancer is one of the most frequent malignancies worldwide,with a highincidence in African region and Western Pacific region.Due to insidious onset and highlymalignant,only25%patients with liver cancer accepted operation treatment.Therefore,non-surgical treatment has been highly valued.New treatment techniques and methods areconstantly emerging,including HIFU.However, there are some problems in the applicationof HIFU,such as the long time of ablation,the interference of acoustic energy,the residualtumor tissues.In order to have a better application,we must improve the efficiency ofHIFU treatment.Experiments done by domestic and foreign scholars have confirmed thatthe ultrasound contrast agent could enhance the ablation effect of HIFU. Ultrasound contrast agent could increase the backscatter signal of red blood cells,improve sharpness and contrast of ultrasound image,and advance the accuracy of ultrasounddiagnosis.Targeted ultrasound contrast agent promots ultrasound imaging into targetedmolecular imaging level.Targeted ultrasound microbubbles can enhance ultrasound image.Atthe same time,as drug carriers,targeted ultrasound microbubbles can also achieve thetargeted drug release, and improve drug efficacy.Some scholars prepared anticancer drugsloaded ultrasound microbubbles and studied its toxic effects on tumor cells.But there werefew studies about the effect of combination of targeted and antitumor drugs loadedultrasound contrast agent and HIFU.So we would like to focus on it.In this work,we preparedVEGFR-2targeted and5-FU loaded ultrasound contrast agent,study its characteristics.The work is the experimental foundation for the next step research,aiming at investigating theeffect of HIFU ablation with targeted and antitumor drugs loaded ultrasound contrast agent.The work was divided into the following three parts:Firstly,the preparation and performance study of5-FU loaded PLGA ultrasoundcontrast agent.5-FU loaded PLGA ultrasound contrast agent was prepared by the double emulsiontechnique and vacuum freezy-desiccation technology;by comparing theappearance,structure,particle size,distribution and drug-loading rate,the best preparationcondition was selected.The results showed that5%PVA,10%SP-80was the bestpreparation condition.The ultrasound microbubbles appeared uniformly spheres with aircore,smooth surface.The mean diameter was289.4±50.8nm.the drug-loading rat was0.5%.Secondly, the experiments of5-FU loaded PLGA ultrasound contrast agent in vitro.5-FU loaded PLGA ultrasound contrast agent was prepared by the best preparationcondition;the ultrasonic imaging ability was observed in vitro;the cytotoxicity to livercancer cell was investigated by CCK-8assay,PLGA ultrasound contrast agent was served ascontrol group.The results showed that5-FU loaded PLGA ultrasound contrast agent couldenhance the ultrasound imaging, and showed cytotoxicity to HepG2cell in vitro.Thirdly,preparation and targeting study of VEGFR-2targeted and5-FU loaded PLGA ultrasound contrast agent.VEGER-2targeted and5-FU loaded PLGA ultrasound contrast agent was preparedby carbodiimide technique.The particle size,distribution and Zeta potential were detected,5-FU loaded PLGA ultrasound contrast agent was served as control group;RH-123markedVEGER-2targeted and5-FU loaded PLGA ultrasound contrast agent was prepared,andobserved by fluorescence microscope;the VEGFR-2targeting ability of VEGER-2targeted and5-FU loaded PLGA ultrasound microbubbles was observed byimmunofluorescence assay, RH-123marked5-FU loaded PLGA ultrasound contrast agentwas served as control group.The results showed that VEGER-2targeted and5-FU loadedPLGA ultrasound contrast agent was prepared successfully,with a mean diameter of374.5±79.1nm and zeta potential of-5.05mv;for5-FU loaded PLGA ultrasound contrastagent,the mean diameter was289.4±50.8nm,the zeta potential was-11.7mv.Theultrasound contrast agent microbbubles marked by RH-123were spherical, welldispersion,and showed as green fluorescence dots.By immunofluorescence assay,weobserved a good adhesion with RH-123marked VEGFR-2targeted and5-FU loadedPLGA ultrasound contrast agent microbbubles and HUVECs,while no adhesion withRH-123marked5-FU loaded PLGA ultrasound contrast agent microbbubles andHUVECs.The VEGER-2targeted and5-FU loaded PLGA ultrasound contrast agentshowed a good VEGFR-2targeting ability in vitro.
Keywords/Search Tags:Ultrasound contrast agent, Vascular Endothelial Growth Factor Receptor2, 5-fluorouracil, Poly(lactic-co-glycolic Acid)
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