Chitosan-Vancomysin Composite Biomaterial as a Laser Activated Surgical Adhesive with Regional Antimicrobial Activity

We have used laser irradiation to enhance the natural adhesiveness of chitosan to form a thin film surgical adhesive. Prevention of infection at surgical sites often utilizes systemic provision of antibiotics with reduced local efficacy and potential side effects. In the work reported here, we investigate the bactericidal properties of laser-irradiated chitosan films and their impregnation with the antibiotic vancomycin. Despite strong efficacy in solution, chitosan films showed no antimicrobial activity against representatives of common pathogens Escherichia coli, Staphylococcus aureus, and S. epidermidis. In contrast, a composite of chitosan adhesive and the antibiotic vancomycin showed therapeutically significant release profiles greater that the Minimum Bactericidal Concentrations (MBCs) for the Staphylococci over a 28 day period. These composite films had greater crystallinity, up to 28 +/- 3 compared to 8.9 +/- 2%, for its unblended counterpart. Despite a significant increase in material strength from 31.4 +/- 4 to 77.5 +/- 5 MPa, flexibility was still maintained with an elongation to break around 5 +/- 2% and fold endurance of approximately 30 +/- 3-folds. Laser irradiation had no apparent effect on the release or activity of the antibiotic which survived transient temperatures at the film tissue interface during infrared irradiation of around 54 degrees C. Furthermore, significant adhesive strength was still apparent, 15.6 +/- 2 KPa. Thus, we have developed a laser-activated bioadhesive with the potential to close wounds while facilitating the prevention of microbial infection through local release of antibiotic targeted to the site of potential infection.