MODIFIED CATECHOL-BASED POLYMERIC BIOMATERIALS FOR ANTIVIRAL, ANTIBACTERIAL, AND HEMOSTATIC APPLICATIONS

The catechol side chain, a key molecule in mussel adhesive proteins, can be modified with electron-donating (e.g., –OH) or electron-withdrawing (e.g., halogens, –NO₂) groups to control its autoxidation. Electron-donating groups promote catechol oxidation, increasing hydrogen peroxide (H₂O₂) generation, which is useful for developing antimicrobial materials. Conversely, electron-withdrawing groups limit oxidation, leading to enhanced crosslinking, interfacial binding, and intrinsic antibacterial properties. These modifications make catechol-functionalized polymers ideal candidates for hemostatic and infection prevention applications. This dissertation focuses on the development of polymeric biomaterials to address challenges in infection control, hemostasis, and tissue adhesion. The projects explore catechol-based modifications to enhance material functionality for these biomedical applications.Project 1 develops a novel polymer coating containing 6-hydroxycatechol, which enhances H₂O₂ production on polypropylene (PP) fabric. The addition of an electron-donating –OH group accelerates autoxidation, generating over 3000 μM of H₂O₂ within an hour, significantly more than unmodified catechol. This coating exhibited strong antimicrobial effects against both Gram-positive and Gram-negative bacteria, as well as antiviral activity against human coronavirus 229E and bovine viral diarrhea virus, reducing viral load by 99.7%.Project 2 introduces 6-chlorocatechol-functionalized gelatin nanoparticles designed for rapid hemorrhage control and infection prevention. These nanoparticles form adhesive films upon hydration, with the addition of an electron-withdrawing –Cl group enhancing crosslinking, mechanical stability, and hemostatic performance. In mouse tail transection and liver hemorrhage models, the nanoparticles achieved rapid bleeding cessation and reduced blood loss. They also demonstrated antibacterial activity against multiple bacterial strains without causing cytotoxicity.Project 3 investigates the effects of different electron-withdrawing groups (–Br, –Cl, –NO₂) on catechol-functionalized gelatin nanoparticles. These modifications improve mechanical properties, adhesive strength, and antibacterial efficacy by promoting crosslinking and non-covalent interactions. 6-Nitrocatechol showed superior antibacterial performance, though it exhibited reduced cytocompatibility compared to other modifications.Overall, this body of work provides insights into developing multifunctional biomaterials for infection control, hemostasis, and tissue adhesion, leveraging targeted chemical modifications to enhance their properties and performance.