Preparation And Animal Imaging Of Multifunctional Magnetic Resonance Contrast Agents Based On Chitosan Derivatives

A series of water-soluble chitosan derivatives and nanoparticles chelated with Gd3+for contrast agent was prepared by chemical modification.Biological toxicity experiments and animal imaging experiments proved that prepared nanoparticles as potential multi-functional magnetic resonance contrast agents were of high efficiency,low toxicity and long residence time in vivo.In the second chapter,the amphiphilic core-shell chitosan(DTPA-OCS)nanoparticle was designed and chelated with Gd3+to prepare MRI contrast agent.Oleic acid and DTPA were modified to chitosan by acyl chloride method.The morphological characteristics of DTPA-OCS were observed by TEM and DTPA-OCS nanoparticle was of core-shell structure.Cytotoxicity experiments and acute pathological examination of tissues revealed that GdDTPA-OCS was of less biotoxicity.Gd-DTPA-OCS magnetic resonance imaging nanoparticles can be enriched in the liver and imaging signal of the liver is significantly enhanced.The experiment of loading doxorubicin initially demonstrated that nanoparticles have the potential to carry hydrophobic drugs.Experiments show that prepared chitosan derivative nanoparticle can be used as a low-toxic potential multi-functional magnetic resonance contrast agent.In chapter 3,DTPA-CS-CM-?-CD was designed prepared through the reaction of water-soluble chitosan DTPA-CS and CM-?-CD.DTPA-CS-CM-?-CD nanoparticle was of core-shell structure.The magnetic resonance imaging agent Gd-DTPA-CS-CM-?-CD was prepared through chelated Gd3+.The TEM observed the morphology of Gd-DTPA-CS-CM?-CD nanoparticle was of that core-shell structure.The in vitro measurement of relaxation time showed that MRI nanoparticles higher relaxation rate.Acute toxicity pathological experiments showed that the prepared nanomaterials were of low toxicity.Prepared MRI nanoparticles were of longer residence time in vivo.MRI nanoparticles can be enriched in the liver and obviously enhanced the imaging signal of liver.The hydrophobic drug doxorubicin can be obviously loaded in the Gd-DTPA-CS-CM-?-CD these nanoparticles.This chapter designs and synthesizes potential multifunctional liver contrast agents with high relaxation rate and low toxicity.