PH-Responsive fluorescent dye-labeled metal-chelating polymer with embedded cadmium telluride quantum dots for controlled drug release of doxorubicin

Abstract

This paper describes the synthesis and characterization of a pH-responsive drug release system based on cadmium telluride quantum dots capped by fluorescent dye-labeled poly (N-(2-(2-amino-ethylamino)-ethyl methacrylamide) metal-chelating polymer. Fluorescent dye is a model for an active molecule which shows our polymer can be attached to bioactive agents such as antibody or a functional drug. Furthermore, it indicates the success of ligand exchange between anchor groups on polymer surface and QDs. The polymer was synthesized using reversible addition fragmentation chain transfer polymerization, resulting in polymers with controllable molecular weights and low polydispersities. The use of diethylenetriamine allows obtaining hydrophilic polymers with amine functional groups available for conjugation with QDs. Furthermore, the amine moieties of the polymer guarantee the pH sensitivity of the system. The obtained nano carrier was monodispersed with very small diameter around 4.5 nm which confirmed by TEM. The obtained nanoparticles show low cytotoxicity in cell viability studies. The release rates of doxorubicin (DOX) anticancer drug conjugates were studied at pH 5.4 and pH 7.4. The release behavior for DOX in pH 7.4 (pH of normal cells) is <1%, while it is high at pH 5.4 (pH of cancer cells).