S1E7
Episode 7 (August 23, 2020)
Yuwei Gu
Northwestern University
Jingjie Hu
Mayo Clinic
Siyuan Rao
MIT
Controlling Polymer Network Topology
Abstract:
Polymer networks (e.g., elastomers, thermosets, and gels) are arguably the most broadly used materials known. Recent studies have revealed that network topology, comprising the ways in which strands are connected in polymer networks, plays a critical role in determining a variety of fundamental material properties. However, due to lack of available strategies and methods, characterizing and controlling/modulating network topology has been rarely achieved and represents one key challenge in the field. In this talk, I will introduce two aspects of PhD works towards solving this grand challenge: 1) Developing general approaches to enhancing mechanical properties of polymer networks by controlling topological defects; 2) Developing novel functional materials by employing topological manipulation as the central design principle. Taken together, I will show that controlling network topology features a powerful yet largely overlooked design-principle to enhance/modulate bulk properties of polymer network materials.
Nanoparticles and Cell Mechanics for Breast Cancer Detection
Abstract:
Targeted therapy and cell mechanics offer emerging opportunities for the early detection and localized treatment of breast cancer. This talk will present a combined experimental and theoretical study of 1) nanoparticle targeting, and 2) the use of cell mechanics in breast cancer detection. In the first part of the talk, the key role of adhesion is presented to provide new insights for the development of targeted nanoparticles for detection of cancer. Combined thermodynamics and kinetics concepts are used to predict nanoparticle entry process. The predictions from the models are shown to be in agreement with experimental measurements of adhesion and in vitro/in vivo observations of nanoparticle entry into normal/tumor cells and tissues. In the second part of the talk, the use of cell mechanics is explored in the development of mechanical biomarkers for the detection of breast cancer outside the body. This involves the shear deformation of single normal/tumor cells that is subjected to the laminar flow in a fluidic chamber, and the use of digital image correlation (DIC) to determine the strain variations within the cells. The results show that there are significant differences in cell viscoelastic properties in normal/tumor breast cells at different stages of tumor progression. The implications of the current study are presented before highlighting new opportunities for future research.
Functional Materials Platform for Neural Circuit Interrogation
Abstract:
Diagnosis of many mental diseases heavily relies on behavioral assessment. To understand the principles of neural circuitry mechanisms and develop effective treatments, it is essential to discover the causative link between behavioral output and cellular activity. Engineering approaches can provide methodological assistance to establish tool platform. Ideally, the tool platform will have the features including minimal invasiveness to biological tissue; functional longevity; widespread coverage of neural circuits; the capability to manipulate neurons at multiple scales, ranging from individual synapse to broad neural circuits; and the specificity to identify targeted neural populations. I have been developing effective engineering tools in neural-material interfaces to investigate the dynamics of neural circuits. This talk will cover my two main research directions: precise interventional tools for remotely controlled neuromodulation and real-time recording techniques to monitor neural dynamics. In my talk, I will first mainly present a magnetic toolkit for remote neuromodulation, which allows remotely controlled release of pharmacological compounds to modulate targeted neural circuits. This chemomagnetic technique combines magnetic tools and behavioral neuroscience to enable temporally precise modulation of specific neural circuits underlying motivation and social interactions. In the second part, I will briefly introduce an optical recording system to monitor neural dynamics from multiple sites across the central nervous system in freely behaving mice with simultaneous behavioral output.