Water-soluble ZnO quantum dots modified by polyglycerol: The pH-sensitive and targeted fluorescent probe for delivery of an anticancer drug

Abstract

Efficacious specific anticancer drug delivery on the tumor site is the basic title of many investigations. In this paper we reported photoluminescence ZnO quantum dots (ZnO QDs) as a pH-responsive platform for delivery of anticancer drug doxorubicin (DOX). Biocompatible ZnO QDs was synthesized using zinc acetate in the alkaline medium. To improve the nanoparticles aqueous dispersion, ZnO QDs are directly functionalized with polyglycerol (PG) through ring-opening polymerization of glycidol. Moreover, folic acid was conjugated to the end of polyglycerol chains through esterification reaction to target the nanoparticles for cancer cells (ZnO QD-PG-FA). These nanocarriers were characterized by different techniques. The HRTEM images confirmed a final size of about 10 nm for ZnO QD-PG-FA. Doxorubicin was loaded on the ZnO QD-PG-FA in a different carrier: drug weight ratios. The photoluminescence property of ZnO QDs was remained after surface modification with PG, FA, and drug loading. The results showed that the drug was immediately released in acidic intracellular environments of tumor cells, while at neutral pH the complex was stable. Cell cytotoxicity assay confirmed the antitumor activity of DOX-ZnO QDs-PG-FA. Therefore, ZnO QD-PG-FA provides a valuable platform that can use as a diagnostic, targeting, and pH-responsive delivery of anticancer drug for tumor therapy.