Cationic Biomimetic Particles of Polystyrene/Cationic Bilayer/Gramicidin for Optimal Bactericidal Activity

Area of Science:

• Materials Science
• Nanotechnology
• Antimicrobial Research

Background:

• Developing effective antimicrobial agents is crucial for combating bacterial infections.
• Nanoparticle-based drug delivery systems offer potential for enhanced therapeutic efficacy.
• Combining different antimicrobial agents can lead to synergistic effects and broader activity.

Purpose of the Study:

• To create and characterize novel nanostructured particles for enhanced bactericidal activity.
• To investigate the incorporation of gramicidin D (Gr) within a cationic lipid bilayer (DODAB) on polystyrene sulfate (PSS) nanoparticles (NPs).
• To evaluate the antimicrobial efficacy of these hybrid nanoparticles against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.

Main Methods:

• Synthesis of PSS nanoparticles.
• Adsorption of DODAB/Gr bilayer onto PSS NPs.
• Characterization of nanoparticle size and zeta-potential.
• Determination of minimal inhibitory concentrations (MICs) against E. coli and S. aureus.

Main Results:

• The PSS/DODAB/Gr NPs exhibited increased zeta-average diameter and a shift from negative to positive zeta-potential.
• Narrow size distributions were observed for the hybrid nanoparticles.
• Maximal microbicidal activity was achieved at very low concentrations of DODAB (0.057 mM) and Gr (0.0057 mM).
• Broad-spectrum activity was demonstrated against both E. coli and S. aureus.

Conclusions:

• Highly-organized, nanostructured, and cationic particles are advantageous for hybrid antimicrobial combinations.
• The PSS/DODAB/Gr NPs provide a promising platform for broad-spectrum antimicrobial activity.
• Significantly reduced concentrations of antimicrobials are effective when incorporated into this nanostructure.