Engineering tough, hygroscopic, and active hydrogels for surgical simulation and anti-biofouling

Hydrogels have emerged as a class of materials useful for a variety of contexts, including tissue engineering, anti-fouling, drug release, medical devices, and flexible electronics. The usefulness of hydrogels in these contexts stems from their structure, consisting of a 3D cross-linked polymer network containing mostly water. This structure leads to a material with tunable, tissue-like softness and water content, biocompatibility, resistance to biological fouling, high porosity, and transparency. However, the utility of these numerous properties is often offset by hydrogel brittleness and, if exposed directly to air, eventual drying. Therefore, hydrogels are difficult to use for applications involving puncture or high shear forces, such as surgical simulation, as well as open-air environments. The goal of my thesis research is to bridge this technological gap by engineering hydrogels that are both tough and non-drying so that new applications may be opened for this unique material. Chapter 2 discusses a general strategy to improve hydrogel toughness by forming a highly concentrated polyacrylamide hydrogel with a low number of cross-links, thereby increasing the polymer entanglements that may form between cross-linking junctions. Chapter 3 demonstrates that the drying of hydrogels exposed to air can be prevented by incorporating glycerol within the gel network, leading to a hygroscopic material that draws humidity from the surrounding ambient air. Both of these properties of toughness and non-drying are combined in Chapter 4 to demonstrate the 3D printing of suturable organ mimics for preoperative planning and surgical training. Further applications of the tough hydrogel in drug release are shown in Chapter 5. In this study, drug-binding cyclodextrin linked within the tough polyacrylamide hydrogel releases its molecular cargo in response to tensile stretching. The tough hydrogels also exhibited anti-fouling properties due to the high water content in the gel. Therefore, they were used for anti-fouling in contexts where physical forces are present. Chapter 6 demonstrates the anti-fouling capabilities of the tough hydrogel by layering it on top of a vibrating dielectric actuator to actively remove pre-formed biofilms. Finally, in Chapter 7, the anti-fouling property of the hydrogel is enhanced by interpenetrating the network with polyvinylpyrrolidone complexed with anti-bacterial iodine to prevent corrosion of stainless steel by sulfate-reducing bacteria. Overall, tough and non-drying hydrogels were successfully engineered and then used for a variety of applications, including model organs for surgical simulation, flexible electronics, drug release, and anti-biofouling.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Ballance, William C

Contributors dc:contributor

• Kong, Hyunjoon
• Sing, Charles
• Rogers, Simon
• Phillips, Heidi

• hydrogel
• toughness
• anti-fouling
• hygroscopic
• polyacrylamide
• 3D printing
• drug release
• cyclodextrin

Statement dc:rights

• Copyright 2020 William C. Ballance

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/108254

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/108254