This week we return to reading some papers about DNA nanotechnology that my PI recommended to me a while ago and I hadn’t read before now.

Paper 1: Rolling Up Gold Nanoparticle-Dressed DNA Origami into Three-Dimensional Plasmonic Chiral Nanostructures by Shen et al. [1]

Today I learned that there is a field of nanotechnology focused on arranging metallic nanoparticles in very precise structures so that they can affect light on the visible spectrum. The authors of this paper demonstrate one such approach that uses DNA origami to arrange gold nanoparticles into helical 3D structures. The idea is that DNA origami is a bottom-up manufacturing approach that has more resolution, precision and flexibility than top-down manufacturing methods like lithography. The authors showed that their structure achieved plasmonic resonance for light with a wavelength of approximately 525nm [1].

One thing the authors did that was particularly interesting to me was that they used a multistage assembly process to make their structure. First, they folded a flat rectangle of DNA origami using one annealing process; then they did a secondary anneal that attached the gold nanoparticles to the sheet, and then finally they performed a tertiary assembly process that rolled the sheet into a tube. The one detail that was missing was what the temperature for the tertiary assembly process was. The secondary anneal ended at room temperature, so perhaps the tube was rolled at room temperature as well, but I would be curious to know for sure what the authors did [1].

Paper 2: DNA Origami Meets Polymers: A Powerful Tool for the Design of Defined Nanostructures by Hannewald et al. [2]

This is a detailed review of the current state of the art in building polymers using DNA origami. They present different strategies for building polymers out of DNA or for using DNA as a templating material for building polymers out of other materials. They indicate that this is an emerging area of research because there are not a large number of papers in the field yet, and they do a good job of highlighting some of the challenges involved that are preventing the field from really taking off [2].

The challenges range from manufacturing-related to characterization of the results of manufacturing. For example, the authors point out that often the steric hindrance of the materials in use can make it difficult for robust assembly to occur. Another challenge they highlighted was that often the yields of the assembly process are too low for characterization using gel electrophoresis, NMR or DLS [2].

## References:

[1] Shen, X., Song, C., Wang, J., Shi, D., Wang, Z., Liu, N., & Ding, B. (2012). Rolling up gold nanoparticle-dressed dna origami into three-dimensional plasmonic chiral nanostructures. Journal of the American Chemical Society, 134(1), 146–149. https://doi.org/10.1021/ja209861x

[2] Hannewald, N., Winterwerber, P., Zechel, S., Ng, D. Y. W., Hager, M. D., Weil, T., & Schubert, U. S. (2021). DNA Origami Meets Polymers: A Powerful Tool for the Design of Defined Nanostructures. In Angewandte Chemie - International Edition (Vol. 60, Issue 12, pp. 6218–6229). John Wiley and Sons Inc. https://doi.org/10.1002/anie.202005907