Thesis Defense Announcement

The Herff College of Engineering announces the Final Thesis Defense of

Logan Boles

for the Degree of Master of Science

June 11, 2018 at 2:00 PM in Engineering Administration Building, Room 202C

Advisor: Jessica Amber Jennings

In Vitro Evaluations of the Effects on Chitosan Paste by the Derivatization of Chitosan

ABSTRACT: Complex musculoskeletal injuries, such as open fractures, are traumatic injuries that can be contaminated by bacteria upon injury or after admittance to a healthcare facility. Infection of these injuries leads to significant morbidity and mortality. Local delivery systems have become popular adjunctive treatments alongside systemic antimicrobial therapy. Systems using chitosan, a natural biopolymer, have been shown to be biocompatible and able to degrade within in the body, but they exhibit bolus release kinetics. This research investigated a combination of a quaternized chitosan derivative, trimethyl chitosan, and a graft copolymer of chitosan, poly(ethylene glycol) diacrylate chitosan, as a local delivery systems for antimicrobials. Efficacy of this system was evaluated by testing antimicrobial elution, activity of eluted antimicrobials, enzymatic degradation properties, cytocompatibility, injectability, and adhesivity. Combination paste eluted active vancomycin and amikacin for 6 and 5 days, respectively, and was almost completely degraded after 14 days. Cytocompatibility of the combination with NIH3T3 fibroblasts was lower than cells grown on blank tissue culture plastic, 87.7% and 86.0% on days 1 and 3, respectively. Similar results were obtained for MC3T3 pre-osteoblasts having 96.3% and 83.0% viability on days 1 and 3, respectively. Combination paste was easily ejected and required 9.40N of force to completely eject from a standard 1 mL syringe. The combination was able to adhere to representative muscle tissue and removed by conditions similar to irrigation used in the management of complex musculoskeletal trauma. These preliminary results indicate that the combination of trimethyl chitosan and poly(ethylene glycol) diacrylate chitosan could be developed for local antimicrobial delivery to prevent infection.