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

Epitaxial Nanocomposite:  A Pathway for Tunable FunctionalitiesQuanxi Jia, State University of New York (SUNY), Host:  Liliana Stan

Epitaxial nanocomposites provide a pathway to produce tunable and improved properties that are often not accessible from the individual constituents. Over the years, new discoveries and major advances have been made to synthesize epitaxial nanocomposite films and to gain fundamental understanding of their physical properties such as ferromagnetism ferroelectricity, and multiferroicity. In this talk, I will overview our effort to understand, exploit, and control competing interactions of a range of epitaxial nanocomposite metal oxide films. Using both ferroelectric and ferromagnetic oxides as model systems, we have illustrated that certain physical properties of the materials could be systematically tuned by controlling the strain state of the epitaxial nanocomposite films. Our phase field simulations have suggested that the ultimate strain in the interested phase is related to the vertical interfacial area and interfacial dislocation density of the epitaxial nanocomposite films.

 

Aug. 8, 2018

Atomic Origami:  A Technology Platform for Nanoscale Machines, Sensors, and Robots,  Itai Cohens, Cornell University, Host: Xiao-Min Lin

What would we be able to do if we could build cell-scale machines that sense, interact, and control their micro environment? Can we develop a Moore’s law for machines and robots? In Richard Feynman’s classic talk ``There's Plenty of Room at the Bottom" he foretold of the coming revolution in the miniaturization of electronics components. This vision is largely being achieved and pushed to its ultimate limit as Moore's Law comes to an end. In this same lecture, Feynman also points to the possibilities that would be opened by the miniaturization of machines. This vision, while far from being realized, is equally as tantalizing. For example, even achieving miniaturization to micron length scales would open the door to machines that can interface with biological organisms through biochemical interactions, as well as machines that self-organize into superstructures with mechanical, optical, and wetting properties that can be altered in real time. If these machines can be interfaced with electronics, then at the 10's of micron scale alone, semiconductor devices are small enough that we could put the computational power of the spaceship Voyager onto a machine that could be injected into the body. Such robots could have on board detectors, power sources, and processors that enable them to make decisions based on their local environment allowing them to be completely untethered from the outside world.In this talk I will describe the work our collaboration is doing to develop a new platform for the construction of micron sized origami machines that change shape in fractions of a second in response to environmental stimuli. The enabling technologies behind our machines are graphene-glass and graphene-platinum bimorphs. These ultra-thin bimorphs bend to micron radii of curvature in response to small strain differentials. By patterning thick rigid panels on top of bimorphs, we localize bending to the unpatterned regions to produce folds. Using panels and bimorphs, we can scale down existing origami patterns to produce a wide range of machines. These machines can sense their environments, respond, and perform useful functions on time and length scales comparable to microscale biological organisms. With the incorporation of electronic, photonic, and chemical payloads, these basic elements will become a powerful platform for robotics at the micron scale.  As such, I will close by offering a few forward looking proposals to use these machines as basic programmable elements for the assembly of multifunctional materials and surfaces with tunable mechanical, optical, hydrophilic properties. 

 

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  
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