BME PhD Preliminary Exam Announcement for Han Dang Nhat Nguyen (C. Lin and J. Liu, co-advisors)
Everyone is invited to attend the public presentation beginning at 3:00 PM EST.
Title: Dynamic Tuning of Hydrogel Stiffness and Viscoelasticity to Probe Cell Behaviors
Date: August 1st, 2022
Time: 3:00 PM EST
Committee: Chien-Chi Lin, Major Professor; Julie C. Liu, Co-Chair; Hiroki Yokota; Sungsoo Na
Abstract:
Hydrogels have proven to be highly useful for 3D cell culture applications as their chemical and mechanical properties can be easily tuned to mimic the dynamic nature of the extracellular matrix within the native
tissues. However, most current biomimetic hydrogel models are elastic and lack tissue-relevant viscoelastic properties such as hysteresis and stress-relaxation. Stress-relaxation refers to a material’s ability to reduce the stress response over time under
a constant force and has been reported to affect many cellular processes including differentiation, proliferation, and cancer progression. In this regard, we have developed viscoelastic hydrogels with tunable stiffness and stress-relaxation rate to investigate
how different cell types respond to changes in matrix physical properties. Specifically, two chemistries, thiol-norbornene photopolymerization and boronic ester dynamic bond were employed to fabricate gelatin-based hydrogels. Gels formed solely via irreversible
thiol-norbornene chemistry are elastic (EL) and non-stress-relaxing while gels formed with both thiol-norbornene and the reversible boronic ester bonds are viscoelastic (VE) and stress-relaxing. We found that osteocytes encapsulated within EL gels and VE gels
displayed significant differences in cell morphology as well as cytokine secretion. Next, we demonstrated that our hydrogels can be dynamically stiffened via an enzymatic reaction to match the mechanics (e.g stiffness and stress relaxation rate) of pancreatic
cancer progression and explored the cells’ transcriptional changes associated with sensing stiffness and viscoelasticity. Finally, future work will be focused on the differentiation of induced pluripotent stem cells (iPSCs) into pancreatic progenitor cells
in EL and VE gels. We anticipate that our versatile hydrogel systems will provide promising means to explore cellular mechanoresponsive mechanisms and pathways.
*Han Dang Nhat Nguyen is inviting you to a scheduled Zoom meeting.
Topic: Han Nguyen Prelim Exam
Time: Aug 1, 2022 03:00 PM Eastern Time (US and Canada)
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Meeting ID: 708 597 2423
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