Smart-AMPs: Decorated Nanostructured Lipid Carriers for Improved Efficacy of Antimicrobial Peptides in Chronically Infected Burn Wounds

Background/Objectives : Burn wound infections present significant clinical challenges due to multidrug-resistant pathogens and the limitations of traditional antimicrobials. While antimicrobial peptides (AMPs) have broad-spectrum effectiveness, their instability in wound environments limits their use. This study compares properties of AMP-decorated nanostructured lipid carriers (NLCs) to free AMPs, focusing on their dermal penetration, retention, and antimicrobial efficacy in simulated ex vivo burn wound models. Methods : AMP-decorated NLCs (smart-AMPs) were produced by electrostatic and hydrophobic surface adsorption and characterized regarding their size, zeta potential, and physical short-term stability. The distribution of AMPs within the wounds was evaluated using an ex vivo porcine ear model with various wound types. The antimicrobial efficacy was assessed by monitoring the bioluminescence of Aliivibrio fischeri as a live bacterial marker for 24 h. Results : The size and zeta potential measurements confirmed the successful formation of smart-AMPs. The dermal penetration of AMPs was influenced by the type of wound and the type of AMP formulation (free AMPs vs. smart-AMPs). In the chronically infected burn wounds, which were characterized by the formation of a biofilm in a protein-rich wound fluid, the smart-AMPs resulted in a 1.5-fold higher and deeper penetration of the AMPs, and the antimicrobial activity was 6-fold higher compared to the free AMPs. Conclusions : smart-AMPs present an innovative approach for treating chronic, biofilm-associated wounds more efficiently than the current treatment options.