I am a soft matter researcher finishing up a PhD in chemical engineering who moonlights as a condensed matter physicist and theorist. I have a deep interest in how the methods and ideas of soft matter physics can be applied to biophysics, robotics, and ecology. I am deeply interested in how nanoparticles, colloids, and a variety of biological systems interact and form complex, ordered assemblies and make collective decisions based on simple rules of interaction.
Current Projects and Interests:
DNA Nano Objects
DNA Nano objects have recently been synthesized to take a variety of shapes including wireframe octahedra, tetrahedra, cubes and icosahedra. These DNA objects can self assemble into crystals by themselves and co-assemble with DNA coated nanoparticles allowing for a vast array of crystal structures not previously accessible to nanoparticles. In collaboration with the Gang Group at Columbia, my work pertains to the crystallization of these complex building blocks. I design models that capture features of complex crystallization processes we are interested in studying within a reasonable timescale. With my collaborators, we update these models to ask questions about the self-assembly process and the mechanisms that allow for optimal self assembly.
Out of Equilibrium Nanoparticle Assemblies
In colloidal systems, equilibrium assemblies are often studied as the norm to explain self assembly and guide design of new building blocks. However, the preparation of the building blocks and the process of assembly necessarily occurs far from equilibrium. This can lead to a mismatch between predicted structures from theory or simulation and experimental crystal structures because of non-equilibrium kinetics can drive different crystal structures to form. Work from the Ye lab at Indiana University and the Chen lab at UIUC has for the first time imaged colloidal crystallization in real time and found some methods to control the assembly pathways of complex crystal structures. My work, in collaboration with the Ye lab and Glotzer lab postdoc Tim Moore, involves controlling and theoretically describing the self assembly and crystallization pathway of anisotropic particles in complex non-equilibrium systems. By understanding the interactions between particles we can simulate these systems to better understand assembly pathways and kinetics, and predict which crystal structures will form. We thereby push the limits of simulating complex nanoparticle systems while learning new fundamentals of engineering assembly pathways for nanoparticle superlattices.
Tunable Gold Nanoparticle Assemblies
I work with gold nanoparticles in a variety of contexts. In my collaborations with the Ye Group and Indiana university I study charged nanocubes constrained to 2D, which you can read more about in the out of equilibrium assembly section. I also work with even more complex systems, including charged tetrahedra in surfactant solutions and model the complex physics underpinning their self assembly into complicated crystal structures.
Biophysics of Cells
A variety of biological systems can be studied from the perspective of colloidal physics. The shape and mechanical properties of cells often dictate how they interact in the body and with each other. In particular, I am interested in how red blood cells self organize depending on their properties. Different blood borne illnesses change the shape, mechanical, and chemical properties of red blood cells. Therefore, understanding how they red blood cells aggregate, self organize, and interact with the body will be essential to detecting, and predicting the effects of blood borne illnesses depending on the properties of the blood.
The properties of cells are often essential in other aspects. A fascinating example is the growth of colonies of E. coli bacteria, where the mobility of bacteria dramatically influences how the colonies grow. Mobility of the bacteria will smooth out local concentration instabilities of bacteria.
Colloidal Tunable Host Guest Assemblies
Nanoparticle host-guest assemblies are a new class of colloidal structures (currently only realized for hard particles) where a ‘host’ particle forms a orientationally restricted ‘cage’ around a more orientationally and vibrationally free ‘guest’ particle at the center of the cage. In these systems, entropy is compartmentalized, meaning that the host has a lower entropy and the guest has a higher entropy, owing to a higher free volume in the host structure. Entropy compartmentalization has already been discovered for both 2D systems and 3D systems.
My work on Host-Guest structures involves tuning the assembly of these structure via simple geometric rules which you can read about in this paper! I have shown in a simple system of tri-tipped concave star particles and convex guest particles, you can tune the guest particle shape to change the underlying crystal structure. I have discovered multiple new 2D host-guest crystals including guest rotators, guest discrete rotator, homo-porous guest crystals (which you can choose based on the guest), and hetero-porous guest crystals. I therefore show that Host-Guest crystals are easily tunable based on guest shape and could be a useful assembly method for assembling high-quality binary crystals.
