One‐Step Formation of “Chain‐Armor”‐Stabilized DNA Nanostructures

TLDR

DNA-based self‑assembled nanostructures enable nanoscale positioning of organic and inorganic objects and are promising as programmable carriers for targeted drug delivery. The authors sought to develop DNA templates that are robust against degradation at high temperatures, low ion concentrations, adverse pH, and DNases. They constructed 6‑helix DNA tile tubes from 24 oligonucleotides bearing terminal alkyne and azide groups, then linked selected ends via a mild click reaction to form covalently interlocked rings (DNA catenanes). The DNA catenanes remained topologically intact in pure water, after EtOH precipitation, and even at 95 °C when all 24 strands were chemically interlocked.

Abstract

DNA-based self-assembled nanostructures are widely used to position organic and inorganic objects with nanoscale precision. A particular promising application of DNA structures is their usage as programmable carrier systems for targeted drug delivery. To provide DNA-based templates that are robust against degradation at elevated temperatures, low ion concentrations, adverse pH conditions, and DNases, we built 6-helix DNA tile tubes consisting of 24 oligonucleotides carrying alkyne groups on their 3-ends and azides on their 5-ends. By a mild click reaction, the two ends of selected oligonucleotides were covalently connected to form rings and interlocked DNA single strands, so-called DNA catenanes. Strikingly, the structures stayed topologically intact in pure water and even after precipitation from EtOH. The structures even withstood a temperature of 95 degrees C when all of the 24 strands were chemically interlocked.