Leveraging Biomaterials For Treating Pseudomonas Aeruginosa Biofilm Infections Through Nanoparticle And Hydrogel Approaches

Bacterial infections and biofilms remain critical challenges in both water systems and chronic wound management. This dissertation presents a multi-faceted approach to developing innovative antibacterial and antibiofilm biomaterials using nanotechnology and enzyme-based strategies. The work is structured around three independent yet, thematically aligned studies.The first study addresses bacterial contamination in water by exploring the synergistic antibacterial effects of iron oxide nanoparticles (IONPs) and the chemical biocide hydrogen peroxide against Pseudomonas aeruginosa. The synthesized magnetite nanoparticles, both bare and polyacrylic acid-coated, improved the efficacy of hydrogen peroxide, which permits the use of lower, less toxic concentrations of peroxide to be used. The polyacrylic acid (PAA) coating on IONPs enhanced colloidal stability, and when combined with hydrogen peroxide, PAA-IONPs significantly reduced bacterial viability. These findings suggest a promising application in industrial water treatment where reduced chemical biocide usage is desired. The second study transitions from environmental to biomedical applications, focusing on enzyme-loaded alginate hydrogels as antibiofilm wound dressings. By incorporating pyruvate dehydrogenase (PDH) into alginate matrices, the hydrogels effectively altered biofilm metabolism, dispersing established P. aeruginosa biofilms and inhibiting new biofilm formation. Mechanical and structural analyses confirmed the suitability of the hydrogels for wound environments, while cytocompatibility was demonstrated in vitro with human cells. Compared to commercial alginate dressings, PDH-loaded hydrogels showed significantly superior antibiofilm performance, without relying on conventional antibiotics. The third study builds on this platform by enhancing the alginate hydrogel system through the addition of carboxymethyl chitosan (CMC), a biopolymer with known antibacterial properties. Composite hydrogels with two oxidation degrees (10% and 25%) were synthesized and evaluated. The 10% oxidized formulation showed superior mechanical integrity and hydration capacity. PDH-loaded OAlg:CMC hydrogels achieved significant biofilm reduction compared to enzyme-free controls, confirming the benefit of combining enzymatic and polymer-based strategies in wound care. Collectively, this work demonstrates the potential of nanomaterials and bioactive enzymes to combat bacterial infections through innovative material design. By addressing both environmental and clinical biofilm challenges, this dissertation contributes to the advancement of antibacterial materials that may ultimately reduce the need for high-concentration biocides and novel antibiotics.