Synthesis, Characterization Of CSTM And Application For Gene Delivery And MR Molecular Probes

To screen a high-quality materials as nanoparticle vectors,insoluble chitosan were modified into CSTM and CSTM-g-PEG-FA. Then CSTM and CSTM-g-PEG-FA were studied as gene and MR molecular probe carries.The first part of my work is synthesis of CSTM and CSTM-g-PEG-FA. First, the chitosan was reacted with 2-Trimethylammoniumethylmethacrylatchlorid(TMAEMC) to synthesis of soluble chitosan derivatives—CSTM, and then the CSTM was modified with PEG and folic acid to obtaine CSTM-g-PEG-FA. Properties of CSTM and CSTM-g-PEG-FA were characterized by Fourier thransform infrared(FI-IR) and proton nuclear magnetic resonance(1H-NMR). The results indicated that TMAEMC reacted with chitosan and PEG-FA reacted with CSTM.In the second part of this study, we produced the CSTM/pDNA nanoparticles and CSTM-g-PEG-FA/pDNA nanoparticles self-assembly and determined the morphological characterization of NPs. Several factors which affect the particle morphology were investigated, including different media solutions, with or without serum, different N/P ratio. Diameters of the NPs were less than 200nm, particle size distribution were symmetry with high zeta potential while the NPs were prepared in the DI water, In the gel retardation experiments, pNDA can be completely wrapped by the he two kinds of complexes, and the two kinds of chitosan derivatives can be well protected pNDA from enzymatic degradation when the N/P ratio of polymer / pNDA greater than or equal 5.In part III of this study, cytotoxicity and transfection efficiency with two kinds of NPs were studied with 293T cell line, which has a high expression of folate receptor.The cytotoxicity of two kinds of chitosan derivatives as well as two kinds of nano-formulations with MTT were determined. The results showed that Cell viability of two kinds of chitosan derivatives or two kinds of nano-formulations were above 70%. It illustrated that both CSTM and CSTM-g-PEG-FA are safe gene vectors. In cell transfection experiments, CSTM/pDNA NPs and CSTM-g-PEG-FA/pDNA NPs have a high transfection efficiency, and transfection efficiency of CSTM-g-PEG-FA/pDNA NPs are higher than the CSTM/ pDNA NPs, indicating that CSTM-g-PEG-FA/pDNA NPs are targeting.In the forth part of this project, CSTM / TPP-SPIO molecular probe was studied on. CSTM / TPP-SPIO molecular probe was prepared in two steps: the first step is to parpare CSTM / TPP NPs based on ionic gelation, and then combined with the SPIO over night. Size of CSTM / TPP-SPIO molecular probe was between 200nm and 280nm, and zeta potential was between 10.0 mv and 16.0mv. Encapusulation efficiency of SPIO was more than 80%.The last part of this study is to examine the Cytotoxicity of CSTM / TPP-SPIO molecular probes in vitro and diagnosis of malignant lymph node with CSTM / TPP-SPIO molecular probes in vivo.In vitro experiments, the results showed that Cell viability of CSTM / TPP-SPIO molecular probe was above 80%. It indicated that CSTM / TPP-SPIO molecular probe is a safe and low toxicity of nano-formulations. In vivo experiments, T1WI signal markedly enhanced, indicating CSTM / TPP-SPIO molecular probe accumulate in the lymph node lesions.