Dendrimer functionalized water soluble magnetic iron oxide conjugates as dual imaging probe for tumor targeting and drug delivery

A tumor targeted and drug-loaded system that is based on folic acid (FA) conjugated to poly(ethylene glycol) (PEG)-modified dendrimers (PAMAM) with paclitaxel (PTX), Cy5.5 fluorophore and superparamagnetic iron oxide (IONPs) (FA-PEG-G3.5-PTX-Cy5.5@IONPs) has been constructed and characterized. The IONPs were stabilized by FA-PEG-G3.5 PAMAM dendrimers. The anticancer drug PTX was conjugated to the dendrimer segments of the amino-stabilized IONPs using biocleavable ester bonds as the linkers, which are acid cleavable and can be used as an ideal drug delivery system. The PEG moiety attached to the PAMAM@IONPs provides the conjugates with excellent solubility and stability in aqueous medium, and the attached FA could facilitate the use of the conjugates as a folate receptor-targeted drug delivery system. These novel PTX-loaded conjugates have the potential to enhance the effect of fluorescence imaging, MRI contrast and cancer therapy in the course of delivering drugs to target sites.