Bifunctional Graphene Oxide Drug Delivery System Based on miR-21 Response for Tumor Imaging and Therapy

Cancer, a category of diseases that pose a serious threat to human health, has received widespread attention in recent years. Although the small-molecule anticancer drug like Doxorubicin (Dox) has obvious therapeutic effects, it lacks targeting ability and is prone to causing cytotoxicity to normal cells or tissues, thus limiting its clinical application. In this study, a novel drug-loaded nanosystem, which was composed of graphene oxide (GO) modified by molecular beacon (MB) and Dox, was developed to respond to small-molecular RNA (miR-21) and release Dox for killing tumor cells. When the nanosystem was internalized by CD44 receptor-overexpressing cancer cells, the MBs on the GO hybridized with the overexpressed miR-21, thereby opening the hairpin structure and allowing the release of Dox in tumor cells. Our research results indicate that this nanosystem has a good inhibitory effect on cancer cells while exhibiting negligible side effects on normal cells. This treatment strategy provides a new approach to the safe delivery of small-molecule drugs.