Quantum Dots for Tumor-Targeted Drug Delivery and Cell Imaging

Abstract

Early detection of cancer and targeted drug delivery, specifically in and around tumors and at concentrations that would decrease the growth rate and/or viability of the tumors, continues to be the primary challenge in the treatment of cancer. In many cases, the malignancy of tumors is detected only at advanced stages when chemotherapeutic drugs become increasingly toxic to healthy cells. To reduce this problem, targeted drug delivery and early detection of cancer cells continue to be investigated extensively. A tumor-targeting drug delivery system generally consists of a tumor-recognition moiety and a drug-loaded vesicle. Detection systems often involve invasive methods, such as tissue biopsy and sophisticated diagnostics tools, such as magnetic resonance imaging. However, there is no known single system currently that is capable of targeting drug delivery and imaging the delivery process simultaneously. An excellent vehicle to accomplish this objective is to develop a single system that is capable of targeting drug delivery and imaging the delivery process simultaneously to monitor the time course of subcellular location. Integration of biomaterials and semiconductor nanocrystal quantum dots (QDs) fields has good potential for addressing the current problems faced in cancer therapy by using biodegradable chitosan (N-acetyglucosamine) for tumor-targeted drug delivery and QDs for noninvasive imaging. The drug-loaded chitosan-encapsulated ZnO:Mn2+ QDs represent a potential platform to deliver tumor-targeted drugs and document the delivery process simultaneously [Hein S, Pers. Comm.]. Doping enables us to tune into desired fluorescence emission. The doping of ZnO with low concentration of manganese is expected to increase the band-gap energy of ZnO with a