Hybrid Quantum dot-based Theranostic Nanomedicines for tumor-targeted Drug Delivery and Cancer Imaging

Abstract

Over the last decade, researchers have paid great interest to multimodal drug-delivery systems. Quantum dots (QDs) are considered one of the most efficient tools used in theranostic applications for diagnosis and therapy due to their unique physiochemical characteristics. QDs are semiconductor crystals in the nano-scale range of 2-10 nm, which exhibit unique photoluminescence characteristics as well as electronic properties such as tunable emission from visible to near infrared wavelengths and superior light stability QDs possess strong photoluminescence with high molar extinction coefficient values, which make them the best candidates for cell labeling and detection of cancer biomarkers. QDs are characterized by symmetric narrow-emission spectra and broad-absorption spectra However, some fears have been raised regarding the toxicity of QDs, especially Cd-containing QDs, due to the release of Cd ions and the generation of reactive oxygen species Therefore, strategies have been developed to reduce their toxicity and enhance their biocompatibility through hybridization with other moieties such as polymers, proteins, polysaccharides or lipids, offering efficient tumor targeting in addition to inhibiting their release into the systemic circulation. This article discusses QD-based nanohybrids for delivery of anticancer drugs in combination with cancer imaging.