Antimicrobial peptide LL-37 on surfaces presenting carboxylate anions

Area of Science:

• Biochemistry
• Immunology
• Materials Science

Background:

• Antimicrobial peptides (AMPs) are crucial components of innate immunity across diverse organisms.
• AMPs typically possess positive charges, facilitating initial interaction with negatively charged bacterial membranes.
• In vitro studies often require high AMP concentrations, exceeding in vivo levels and potentially causing host cell toxicity.

Purpose of the Study:

• To investigate the effect of localized antimicrobial peptides (AMPs) on bacterial killing and host cell toxicity.
• To explore the potential of self-assembled monolayers (SAMs) for controlled immobilization of AMPs.
• To determine the optimal surface density of LL-37 for effective antimicrobial action with minimal host cell damage.

Main Methods:

• Fabrication of mixed self-assembled monolayers (SAMs) with controlled surface densities of LL-37.
• Utilizing electrostatic interactions to immobilize LL-37 on polyanion substrates.
• Assessing bacterial attraction, killing efficacy against Pseudomonas aeruginosa, and cytotoxicity towards human corneal epithelial cells.

Main Results:

• Immobilized LL-37 on SAMs effectively attracted Pseudomonas aeruginosa.
• A threshold surface density of LL-37 was identified for near-complete bacterial killing.
• Localized LL-37 demonstrated significantly reduced toxicity to human corneal epithelial cells compared to high solution concentrations.

Conclusions:

• Localization of AMPs, such as LL-37, on appropriate substrates enhances bactericidal activity.
• Controlled surface density is critical for maximizing antimicrobial efficacy while minimizing host cell toxicity.
• This approach offers a promising strategy for developing targeted and safer antimicrobial therapies.