Argonne National Laboratory

Colloquium Series

The Center for Nanoscale Materials holds a regular biweekly colloquium on alternate Wednesdays at 11:00 a.m. in Bldg. 440, Room A105/106. The goal of the series is to provide a forum for topical multidisciplinary talks in areas of interest to the CNM and also to offer a mechanism for fostering interactions with potential facility users.

Committee Members:

  • Xiao-Min Lin (Chair)
  • Pierre Darancet
  • Ralu Divan
  • Xuedan Ma
  • Elena Rozhkova
  • Jianguo Wen
Date Title
Jun. 27, 2018

Extending The Scale and Enhancing the Yield of Self-Assembled StructuresJames Alexander Liddle, National Institute of  Standards and Technology (NIST), Host: Ralu Divan

Self-assembly is ubiquitous in biological systems, but remains challenging for synthetic structures. These typically form under diffusion-limited, near-equilibrium conditions. DNA-mediated self-assembly is a powerful method with which to build multi-functional, molecularly-addressable nanostructures of arbitrary shape. While there have been many recent developments in DNA nanostructure fabrication that have expanded the design space, fabrication based on DNA alone can suffer from low yields and is hampered by the need to strike a balance between size and mechanical rigidity.1,2 Despite recent efforts,3 typical assembly protocols, employing large numbers of discrete components, offer little control over the assembly pathway, limiting structure size, complexity, and yield.

We have been working to both understand the factors that limit the yield of self-assembled structures, and to devise approaches to overcome them. In this talk, I will discuss our attempts to build a simple, but predictive model, that describes the process of forming a single fold in a DNA origami structure. Using this model, we show that yield decreases exponentially as a function of the number of discrete components used to assemble a structure. To circumvent this limit, we have developed a two-stage, hierarchical self-assembly process, to create large structures with high yield.4 Our process employs a limited number of discrete, sequence-specific element to shape the structure at the nanoscale and control the large-scale geometry. A generic building block – a DNA binding protein, RecA – rigidifies the structure without requiring any unnecessary information to be added to the system.
Expanding the self-assembly toolbox by blending sequence-specific and structure-specific elements, enables us to make micrometer-scale, rigid, molecularly-addressable structures. More generally, our results indicate that the scale of finite-size self-assembling systems can be increased by minimizing the number of unique components and instead relying on generic components to construct a framework that supports the functional units.
 
1 Murugan, A., Zou, J. & Brenner, M. P. Undesired usage and the robust self-assembly of heterogeneous structures. Nat. Commun. 6, 6203, doi:10.1038/ncomms7203 (2015). 2 Schiffels, D., Liedl, T. & Fygenson, D. K. Nanoscale structure and microscale stiffness of DNA nanotubes. ACS Nano 7, 6700-6710, doi:10.1021/nn401362p (2013). 3 Dunn, K. E. et al. Guiding the folding pathway of DNA origami. Nature, doi:10.1038/nature14860 (2015). 4 Schiffels, D, Szalai, V. A., Liddle, J. A., Molecular Precision at Micrometer Length Scales: Hierarchical Assembly of DNA–Protein Nanostructures, ACS Nano, 11, 6623, (2017)Jul. 13, 2018

Jul. 25, 2018 Quanxi Jia, State University of New York (SUNY), Host:  Liliana Stan
Aug. 8, 2018  Itai Cohens, Cornell University, Host: Xiao-Min Lin
Sep. 5, 2018 Dongling Ma, Institut National de la Recherche Scientifiue (INRS), Host: Gary Wiederrecht
Sep. 19, 2018 Stephan Lany, National Renewable Energy Laboratory (NREL), Host: Maria Chan
Oct. 3, 2018 Haiyan Wang, Purdue University, Host: Jie (Joyce) Wang
Oct. 17, 2018  
Oct. 31, 2018 Haiyan Wang, Purdue University, Host: Joyce (Jie) Wang
Nov. 14, 2018

Stephen G. Sligar, University of Illinois, Host: Elena Rozhkova

Dec. 12, 2018 P. James Schuck, Columbia University, Host: Pierre Darancet
Jan. 16, 2019 Juejun Hu, Massachusetts Institute of Technology (MIT), Host: Peijun Guo