Research

Synthesis of the next generation of functional polymeric materials hinges on our ability to efficiently direct the assembly of polymer molecules at length scales comparable to lamellar growth. Our group seeks to combine aspects of Polymer Crystal Engineering, Microfluidics, and In-Situ Transmission Electron Microscopy to drive our understanding of molecular scale dynamics and entropic transitions associated with polymer entanglement and organization. We apply these fundamental techniques to difficult problems in polymer science, manufacturing, brain health, and global food security and sustainability.

Drawing inspiration from nature's complex structural models, research in the Soft Matter Innovation Lab + Education (SMIL+E) uses in-situ transmission electron microscopy, and multimodal characterization techniques to focus on the following areas:

1) Polymer crystalization and hierarchical polymeric materials

Mechanisms of polymer crystallization and nanoscale manufacturing of hierarchical materials

Much literature addresses 1D, 2D, and 3D hard confinement of polymers. To address gaps associated with 2D and 3D soft confinement of polymers we are optimizing microfluidics methods for polymer crystallization. Our methods enable 2D and 3D soft confinement of soft materials using our controllable hydrodynamic flow field devices. Modern advancements in dynamic microfluidics, pioneered by the lab of Charles Schroeder at UIUC, have led to the development and utilization of automated hydrodynamic particle traps based on generation of stagnated point flow fields.

The underlying principle of the hydrodynamic trap is active feedback control of a stagnation point flow field to guide particles at the trap center and maintain the center-of-mass position of the trapped particle at the trap center in two dimensions. When low Reynold’s number flow conditions are met for the microfluidic device it becomes possible to neglect fluid inertia and numerically describe the flow field condition as a series of conservation equations.

We use this system to facilitate polymer crystallization, study tunable interfaces, and to explore dynamic confinement effects on assembling soft matter. Using engineering design, we fabricate new microfluidic devices in alignment with our various polymer processing applications. Experimental parameters and attainable forces of our trapping devices are in alignment with nanoscale polymer diffusion and lamellar dimensions. Additionally, the dynamic nature of this system (automated pressure and flow control), enables us to create a dynamic soft confinement interface. To gain the most capability from this setup, we couple machine learning models with flow control outputs and train machine learning architectures to automatically adjust flow field dynamics to steer reaction conditions in real-time.

2) Tau protein misfolding 

Assembly and structure of aggregating tau proteins associated with degenerative brain disease

Tau protein misfolding is associated with several neurodegenerative diseases. In collaboration with physicians, this research thrust aims to :

1. Provide a clearer understanding of agonist pathways associated with tau protein monomer mutation towards neurogenerative states 
2. Onset of tau protein fibril formation 
3. Determine feasibility of high throughput characterization of evolving tau proteins using liquid phase transmission electron microscopy (LP-TEM) coupled with machine learning (ML) and microfluidics flow devices.

These aims address limitations on several fronts. Through use of LP-TEM, our research enables in-situ observation and dynamic characterization of evolving protein conformational states. This is in contrast to traditionally utilized cryoelectron microscopy (cryoEM) workflows that are limited to static protein states preserved in cryogenic temperature environments. CryoEM techniques are extremely relevant and currently unrivaled in obtainable structure resolution of protein structural analysis. With advances in LP-TEM device fabrication and associated decreases in liquid cell liquid layer thickness, liquid phase TEM techniques are becoming increasingly better at resolving fine protein structures with the added capability of imaging biologics in their native liquid environments. Operating in such liquid mediums enables the study of native protein structure and additionally does not restrict protein morphological fluctuations that may occur in response to dynamic changes in the protein environment. In LP-TEM, Brownian tomography (single particle analyzed during Brownian rotation) and Brownian particle analysis (hundreds to thousands of particles are imaged simultaneously and class averaged to extract a 3D protein structure) methods are utilized to study protein structures.

 

 

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