Poly(N-isopropyl-acrylamide) (PNIPAM) is a thermoresponsive polymer with a wide range of biological applications, including drug delivery, biosensing, and tissue engineering. The tunability of the structural and mechanical properties of PNIPAM makes it particularly at- tractive in emulating cell environments and dynamic cytoskeletal deformations. This thesis discusses PNIPAM's properties and applications in different forms i.e., solution, brushes, hydrogels, and surface patterned hydrogels, with specific focus on lithographically patterned substrates coated with PNIPAM films. The scaffolds are investigated for structural and me- chanical responses to thermally driven changes in the PNIPAM hydration states using atomic force microscopy (AFM). AFM measurements on our lithographically patterned substrates show that the substrate pattern and coating method enable the fabrication of scaffolds with different topographic and mechanical properties across a wide thermal range. Importantly, these scaffolds exhibit variations in both lateral topography and Young's modulus, rendering them well suited for investigations of differential mechanical stresses experienced by cells and cell membranes. / Master of Science / Poly(N-isopropyl-acrylamide) (PNIPAM) is a polymer which can change its water absorption depending on the temperature of its aqueous environment. It transitions from a swollen state at room temperature to a collapsed state at around 32 °C. These thermally tunable properties make PNIPAM an attractive candidate in a variery of applications, including biomedical and biophysical applications. In this thesis, PNIPAM is coated on lithographically patterned substrates to emulate the cellular cytoskeleton. Atomic force microscopy (AFM) measurements are performed to measure the topography and mechanical properties of the fabricated scaffolds. The results show that the coating method and the features of the used substrate allow the fabrication of different surface topographies with biologically relevant mechanics.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/111536 |
| Date | 16 August 2022 |
| Creators | Chen, Chi |
| Contributors | Physics, Ashkar, Rana, Kaplan, Cihan Nadir, Nguyen, Vinh |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, text/html, application/pdf |
| Rights | Creative Commons Attribution 4.0 International, http://creativecommons.org/licenses/by/4.0/ |
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