Programmable Functional Silicification of DNA Origami Nanostructures.

The silicification of DNA origami nanostructures offers a powerful strategy for enhancing their mechanical stability and resistance against detrimental environmental conditions. In the past years, several studies have investigated key aspects of the silicification process, resulting in a variety of established protocols. However, until now, the silica coating generally served as a passive protective layer or as the base for the further deposition of inorganic materials, but it did not carry any additional functionality itself. Here, we introduce two complementary, programmable approaches for the direct fabrication of functionalized silica coatings of DNA origami nanostructures. First, we synthesized a fluorescein-bearing silica precursor which imparts fluorescence to the silica coating of both individual DNA origami nanostructures and crystals, enabling intracellular tracking of silica-stabilized structures. Second, we employed a silica precursor containing a disulfide bridge to generate a redox responsive silica coating that degrades in a reducing environment. By introducing functionality at the precursor level, our approach establishes silicification as a modular platform for constructing responsive and traceable DNA-based hybrid materials. These strategies expand the chemical scope of DNA nanotechnology and facilitate future applications in drug delivery and advanced materials science.