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Biomaterials

Biomaterials - Poster Session B

Poster C3 - Electrospun Chitosan Membranes Loaded with Bupivacaine and Cis-2-Decenoic Acid Reduce Bacterial Load in Contaminated Burn Wounds

Thursday, October 24, 2024
2:45 PM - 3:45 PM EST
Location: Exhibit Hall E, F & G

Introduction:  Burn injuries are prone to the threat of wound infections. Gram-negative Pseudomonas aeruginosa can rapidly establish a foothold in burn wounds, constructing protective biofilm structures within hours of the initial trauma. Standard wound management includes topical microbial agents, such as silver sulfadiazine cream and nylon dressings like Silverlon. While these treatments have demonstrated effectiveness in reducing microbial colonization, they may have the unintended consequence of delaying the overall wound-healing process and do not address pain management. Electrospun chitosan nanofibrous membranes (ESCM) exhibit several favorable characteristics that make them well-suited for wound healing applications, including their high biocompatibility, biodegradability, the capacity to closely resemble the natural extracellular matrix structure, and a high surface area that enhances cellular interactions and potential for therapeutic delivery. This study evaluated the antimicrobial effects of local anesthetics bupivacaine (BUP), cis-2-decenoic acid (C2DA), and combinations released from ESCM for the treatment of burn wounds.

Materials and

Methods:  Chitosan was dissolved at a concentration of 5.5% (w/v) in a solvent mixture of 70% trifluoroacetic acid and 30% dichloromethane and electrospun at 26 kV. Post-electrospinning, the ESCM were treated with 1:4 ratio of decanoic anhydride: pyridine solution. ESCM were sterilized and loaded with either 35 mg/mL C2DA or a combination of the C2DA and 40 mg/mL BUP (Combo).

Adult male and female Wistar rats were randomly divided into groups (n=6 per group) and anesthetized with isoflurane inhalation. The rat comb scald model established by Regas and Ehrlich was used to create symmetric scald burns using a heated brass comb with 4 prongs (1x2 cm) separated by three 5 mm notches. The injury sites were inoculated with 20 μL Pseudomonas aeruginosa. The scalded skin on one side served as the no-treatment control, and the other side was dressed with application of ESCM, silver sulfadiazine cream, or Silverlon dressing.

Rats were euthanized at 3 days post-wound, at which time tissue biopsies were obtained for enumeration of bacterial colony-forming units (CFU) that were manually counted.

Results, Conclusions, and Discussions: The ESCM + Combo loaded with both C2DA and BUP produced a log CFU decrease in bacterial load comparable to the commercial control silver sulfadiazine cream. This was in contrast to the ESCM + C2DA dressing, ESCM dressing alone, and Silverlon dressing, which did not exhibit significant log CFU decrease. Due to high variability, the ESCM + BUP dressing was excluded from data analysis as shown in Figure 1. Overall, this suggests that the synergistic effort of the C2DA and BUP are crucial to reducing the bacterial load than the individual components or ESCM dressing alone. Moreover, the ESCM + Combo could be a more favorable alternative to the commercial silver-based control, particularly given its potential to reduce the need for frequent reapplication. Nevertheless, future research with a larger sample size is needed to definitively evaluate the in vivo performance of the ESCM + Combo dressing.

Acknowledgements (Optional):