Folding an RCA Scaffold into an Intelligent Coiled Nanosnake for Precise/Synergistic RNAi-/Chemotherapy of Cancer

An RCA product is a promising scaffold for the construction of DNA nanostructures, but so far, there is no RCA scaffold-based dynamic reconfigurable nanorobot for biological applications. In this contribution, we develop an intracellular stimuli-responsive reconfigurable coiled DNA nanosnake (N-Snake) by using incomplete aptamer-functionalized (A) DNA tetrahedrons (T) to fold a long tandemly repetitive DNA strand synthesized by rolling circle amplification reaction (R) with the help of palindromic fragment (P). A DNA-assembled product, ARTP, including spiked aptamers, can retain the structural integrity even if exposed to fetal bovine serum (FBS) for 24 h and displays substantially enhanced target molecule-dependent cellular internalization efficiency. ARTP contains tetrahedral containers and linear containers, so that there are 500 doxorubicins (DOXs) and 12.5 siRNAs per ARTP. Moreover, ARTP can precisely transport anticancer drugs to cancerous sites and controllably release via the structural reconfiguration upon intracellular stimuli, almost 100% inhibiting tumor growth without detectable systemic toxicity owing to the synergistic RNAi-/Chemotherapy. Apparently, coiled N-snake, DOX/siPlk1-loaded ARTP, can specifically enter tumor cells, uncoil upon intracellular stimuli, and attack the cells from the inside, exerting precise cancer therapy.