The Preparation And Detection Of N-carboxymethyl Chitosan Coated Iron Oxide Magnetic Nanoparticles Loaded With Iodine For MR/CT Dual-imaging

Computed tomography(CT)is a non-invasive medical diagnostic technology,which is widely used in diagnostic process.It shows clearer imaging about the gastrointestinal,liver,cardiovascular,bone and tumor.But this technology also has some disadvangtages such as low resolution on brain tissue,soft tissue(muscles,tendons),the cartilage and other tissue.Magnetic resonance imaging(MRI)is also widely used for non-invasive medical diagnostic technologies.MRI imaging has a high resolution on soft tissue,but the MRI equipment is so expensive thus cause limitations on its application.CT Imaging together with MRI imaging techniques both have their advantages and disadvantages.Higher valuable medical diagnosis can be obtained by combining these two kinds of imaging techniques.Nowadays,commonly used clinical CT contrast agents are compounds of iodine,such as lipiodol,iohexol,etc.Lipiodol is an oily preparation of inorganic iodine combined with vegetable oil.With a high iodine content(30%-40%w/w),lipiodol became a high appliable contrast agent in CT Imaging.MRI imaging Contrast agent is commonly divided into ParaMagnetic,SuperParaMagnetism and iron magnetic.ParaMagnetic contrast agents such as grape gadopentetic acid amine are used to shorten the T1 relaxation time as well as enhancing the signal;superparamagnetic contrast agents and magnetic contrast agents such as iron oxide nanoparticles are used to shorten the T2 relaxation time.Iron oxide nanoparticles are widely used in MRI Imaging owning to their good biocompatibility and high sensitivity.Drug delivery system combines various good biocompatibility carriers with drugs so that they can control the drug release speed and appropriate concentration in living organisms,so as to achieve long-term effects.Carboxymethyl Chitosan has good biocompatibility,and can combinate with drugs with covalent bonds,which makes it a good drug delivery carrier.In this paper,we combinated carboxymethyl Chitosan together with acetylatied magnetic nanoparticles,then loaded with iodized oil for MRI,CT dual-mode imaging.Meanwhile,anticancer drug doxorubicin hydrochloride was loaded on that magnetic nanoparticles by covalent modification.As a result,we obtained the modified magnetic nanoparticle for MRI,CT dual-model imaging,and drug sustainable delivery.Our Main contents and results include:(A)The preparation of carboxymethyl-Chitosan magnetic nanoparticlesA modified solvothermal reaction method was applied to synthesize PEGylated magnetic particles,then the composite was modified with carboxymethy chitosan to increase its aqueous solubility,biocompatibility,loading capacity.Then detailed characterization and biocompatibility of the magnetic nanoparticles were performed.The result showed that the carboxymethyl Chitosan magnetic nanoparticles are about 100nm in diameter,and with good magnetic,water solubility and biocompatibility,which make these carboxymethyl Chitosan magnetic nanoparticle a safe carrier.(B)Loading of Iodinated oil on carboxymethyl Chitosan magnetic nanoparticlesTheCarboxymethyl Chitosan magnetic nanoparticles were loaded magnetic lipiodol and then measured its loading capacity of iodized oil as well as stability.The biocompatibility and CT/MRI image capacity were also evaluated.The result shows that the as prepared carboxymethyl Chitosan magnetic nanoparticles were with good loading capacity,stability,biocompatibility and CT/MRI imaging capacity.Hence,the carboxymethyl Chitosan magnetic nanoparticles loaded with lipiodol are a promising contrast-enhanced dual-mode agent for CT and MRI.(C)Loading of doxorubicin hydrochloride on magnetic nanoparticlesThrough covalent modification we loaded magnetic nanoparticles with doxorubicin hydrochloride,which makes it valid foracting as CT/MRI dual-mode imaing agent as well as cancer treatment.Then we measured the drug-loaded nanoparticles drug delivery function,sustainable release capacity and Cytotoxicity.Results showed that the composite exhibited a good drug loading capacity and a sustained-release action.In vitro cytotoxicity test,it also confirmed that contained doxorubicin hydrochloride compound nanoparticles are toxic to tumor cell.