Preparation Of MRI Contrast Agent Based On Chitosan And Its Relaxation

As a naturally occurring polysaccharide,chitosan shows many unique properties, such as biocompatibility,biodegradation,low toxicity and biological activity.Many derivatives have been prepared to meet different needs.In this paper,the development of modification of chitosan and the application of its derivatives were introduced. First,we have synthesized several chitosan derivatives with different substituting group,such as AA,DTPA and Ga.Then,these CS derivatives are prepared for chelating Gd³⁺.the Chemical structure and morphology of these CS derivatives were characterized with ¹H NMR,¹³C CP/MAS NMR spectroscopy,ultraviolet spectroscopy and Transmission electron microscopy.We have studied their relaxation in the pure water.The results show,these CS derivatives presented good water solubility and good relaxation ability.And then evaluated their toxicity in vitro,as a result,CS-Ga-(Gd-DTPA)_n has better biocompatibility than Gd-DTPA which is one of commercial magnetic resonance imaging contrast agent.Therefore,the compound CS-Ga-(Gd-DTPA)_n can be used for further study for macromolecular contrast agents.