| Highly branched polymers are polymerized by ABx monomers(x≥2, A,B are reactive groups), by which fully branched regular dendrimers or irregular polydisperse hyperbranched polymers can be attained. Due to their unique branching units, hyperbranched polyers have different attribution from other polymers. They are characteristic of high solubility, low viscosity, a large number of functional end group and intramolecular holes. In biomedical field, hyperbranched polymers have already revealed promising prospect. Given their hole structure in nano dimension, they can be employed for chelation of metal ions, absorbance of small molecules, transferring and release of drugs. They contain a lot of reactive functional end group, so it's biologically active and can be used as agents of gene delivery, active agents of anti-cancer and medical diagnosis sensors.In this project, we synthesized a series of hydrophilic hyperbranced polyglycidos of different branching degrees, molecular weights, functional groups(-OH,-COOH,-NH2).Through end-group modification, we attached alkyl chains of different length (C5,C8,C18) onto hyperbranched polyglycidols in different modification percentage. In this way we got amphiphilic hyperbranched polymers. We successfully encapsulated hydrophobic QDs by these amphiphilic hyperbranched polymers. The encapsulated QDs are homogenous, stable, dispersed in water and maintain their original fluorescence intensity with multifunctional group on the surface. We attached chelators DTPA,DOTA onto the surface of HPG to produce hyperbranched polymer with multiple chetators. After chelation, we got luminescent Lanthanide complex.Encapsulated QDs can be conjugated with antibodies and have already demonstrated great application in cell imaging and in vitro imaging.HPG with multiple Gd molecules can be used as contrast in MRI imaging, and after attachment with antibodies it can be applied as targeted contrast with specific aggregation in body. Multiple Lanthanide metal complex has stronger luminescence than single Lanthanide metal complex, and can be detected as signal itself with ICP-AES... |
