Directing Assembly and Disassembly of 2D MoS₂ Nanosheets with DNA for Drug Delivery

Layer-by-layer (LbL) self-assembled stacked Testudo-like MoS₂ superstructures carrying cancer drugs are formed from nanosheets controllably assembled with sequence-based DNA oligonucleotides. These superstructures can disassemble autonomously in response to cancer cells' heightened ATP metabolism. First, we functionalize MoS₂ nanosheets (MoS₂-NS) nanostructures with DNA oligonucleotides having thiol-terminated groups (DNA/MoS₂-NS) via strong binding to sulfur atom defect vacancies on MoS₂ surfaces. The driving force to assemble into a higher-order DNA/MoS₂-NS superstructure is guided by a linker aptamer that induced interlayer assembly. In the presence of target ATP molecules, these multilayer superstructures disassembled as a consequence of stronger binding of ATP molecules with the linking aptamers. This design plays a dual role of protection and delivery by LbL stacked MoS₂-NS similar in concept to a Greek Testudo. These superstructures present a protective armor-like shell of MoS₂-NS, which still remains responsive to small and infiltrating ATP molecules diffusing through the protective MoS₂-NS, contributing to an enhanced stimuli-responsive drug release system for targeted chemotherapy.