Investigation of the Injectability, Cytocompatibility, Thermal Response, and Drug Release Capability of Dynamic Poly (Ethylene Glycol) Hydrogels




Otakpor, Mackenzie

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Hydrogels are versatile biomaterials composed of hydrophilic polymers that are crosslinked to form a network. Hydrogels are often used to mimic the extracellular matrix (ECM), which contains macromolecules that aid in the physical and chemical support of cells. In addition, they can be utilized as drug delivery systems, wound healing dressings, and materials for cell growth. In all these applications, the properties of the hydrogels must be tailored to match the distinct characteristics of various tissues in the body and to provide the function needed. For this reason, the hydrogel’s stiffness, stress-relaxation properties, ability to present and release growth factors and therapeutic agents, cell encapsulation capabilities, and cytocompatibility must be optimized. Our collaborative group previously reported the development of dynamic poly (ethylene glycol) (PEG) hydrogels crosslinked via reversible thiolMichael covalent bonds. The equilibrium nature of these bonds permits modulation of the properties of the hydrogels in response to changes in pH, temperature, and photothermal stimuli. Our laboratory is specifically interested in photothermal modulation of the hydrogels through the laser activation of entrapped poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles since this provides the means to tailor the hydrogel’s properties externally with spatiotemporal control and opens the doors to applications in on-demand drug delivery. The work herein described focuses on studying the factors that affect the hydrogel’s injectability, cytocompatibility, stability, thermal response, and drug release capabilities. This thesis is broken up into two parts. One part focuses on the injectability, rheology, and cytocompatibility of dynamic hydrogels prepared with 4-arm PEG macromers with benzalcyanoacetamide end groups (PEG-RBCA) and 4-arm PEG macromers with thiol end groups (PEG-SH). The second part focuses on the thermal behavior, stability, drug release, and cytocompatibility of more stable hydrogels including dynamic PEGRBCA/PEG-SH crosslinks and nondynamic PEG-SH/PEG-Maleimide crosslinks.



hydrogels, biomaterials, cytocompatibility, photothermal modulation


Otakpor, M. (2023). Investigation of the injectability, cytocompatibility, thermal response, and drug release capability of dynamic poly (ethylene glycol) hydrogels. Honors College, Texas State University.


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