UC Irvine

Contact lenses contaminated by pathogenic fungi and bacteria cause eye infections, resulting in ~1 million doctor’s office visits every year, at a cost of $175 million annually in the USA alone. The most severe of these infections are plagued by protective biofilm, which make the microbes more tolerant to current drug therapies, and creates an urgent need for alternative strategies. In my thesis research, material and topographical solutions inspired by nature are explored. I investigated the use of the biopolymer chitosan, which is antimicrobial, biocompatible, plentiful, and inexpensive. The anti-biofouling surface structures found on cicada wings, shark skin, and fish scales are used as inspiration for nanopillars imprinted on chitosan. The fabricated surfaces can prevent biofouling and influence the mechanical performance of the material.The specific goals of this dissertation are to: 1) Fabricate, characterize, and optimize the design of a chitosan hydrogel film with nanopillars which remain stabilize even after immersion in liquid; 2) Evaluate the antimicrobial efficacy of the chitosan hydrogels with nanopillars against Fusarium oxysporum and Pseudomonas aeruginosa; and 3) Investigate the link between the mechanical performance and nanopillar surface on the chitosan hydrogels. I demonstrated in this thesis a scalable process to fabricate bioinspired nanopillar surface structures. The bioinspired surface generally enhances the antimicrobial efficacy and mechanical performance of several types of hydrogel films. The generalization of this technique has important implications and commercial potential.