Highly Efficient Fabrication And Biomedical Applications Of Chitosan-based Hybrid Nanogels

Nanogels are nano-scaled three-dimensional networks,generally with good hydrophilicity and stability.Chitosan,as a natural macromolecular polysaccharide,has a great of advantages such as its good biological compatibility,non-toxicity and biodegradability which has aroused scientists' wide attention and research interest.Fabricating the nanogels from natural macromolecules,such as chitosan,will provide the nanogels with good biocompatibility.Utilizing the natural polysaccharide-chitosan as the main building block,the free radical copolymerization of methyl acrylate(MA)was initiated at the hydroxyl carbon of chitosan and the nanoscale aggregates were induced by the self-assembly of the hydrophobic copolymer graft chains.By introducing the redox-responsive cross-linker to lock the structure,the tumor environment sensitive chitosan-copolymer nanogels were obtained.Study on this facile “Grafted copolymerization Induced Self-Assembly(GPISA)” method has proved that the size and morphology of the nanogels can be controlled via adjusting synthetic parameters.Five kinds of vinyl group-bearing esters with different hydrophobicities were selected to determine the effect of monomer hydrophobicity on GISA and the university of this method.Furthermore,the nanogels were modified by near infrared(NIR)and magnetic resonance(MRI)molecules to synthesize the fluorescence / MRI dual-functional nanogels.The cell toxicity evaluation was performed in LECs,MCF-7 cells by MTT assay.Characterization results of imaging demonstrated that the nanogels were with great cell-labelling capacity and good biocompatibility.The in vivo MRI of lymph node demonstrated the imaging of rat.All these results indicated that the bio-functional nanogels had great potential as near-infrared imaging and MRI agents for diagnosis and therapy of tumor.