Antimicrobial peptide-grafted PLGA-PEG nanoparticles to fight bacterial wound infections

António Miguel Ramôa, Filipa Campos, Luís Moreira, Cátia Teixeira, Victoria Leiro, Paula Gomes, José das Neves, M. Cristina L. Martins*, Cláudia Monteiro*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Wound infection treatment with antimicrobial peptides (AMPs) is still not a reality, due to the loss of activity in vivo. Unlike the conventional strategy of encapsulating AMPs on nanoparticles (NPs) leaving activity dependent on the release profile, this work explores AMP grafting to poly(d,l-lactide-co-glycolide)-polyethylene glycol NPs (PLGA-PEG NPs), whereby AMP exposition, infection targeting and immediate action are promoted. NPs are functionalized with MSI-78(4-20), an equipotent and more selective derivative of MSI-78, grafted through a thiol-maleimide (Mal) Michael addition. NPs with different ratios of PLGA-PEG/PLGA-PEG-Mal are produced and characterized, with 40%PLGA-PEG-Mal presenting the best colloidal properties and higher amounts of AMP grafted as shown by surface charge (+8.6 ± 1.8 mV) and AMP quantification (326 μg mL−1, corresponding to 16.3 μg of AMP per mg of polymer). NPs maintain the activity of the free AMP with a minimal inhibitory concentration (MIC) of 8-16 μg mL−1 against Pseudomonas aeruginosa, and 16-32 μg mL−1 against Staphylococcus aureus. Moreover, AMP grafting accelerates killing kinetics, from 1-2 h to 15 min for P. aeruginosa and from 6-8 h to 0.5-1 h for S. aureus. NP activity in a simulated wound fluid is maintained for S. aureus and decreases slightly for P. aeruginosa. Furthermore, NPs do not demonstrate signs of cytotoxicity at MIC concentrations. Overall, this promising formulation helps unleash the full potential of AMPs for the management of wound infections.

Original languageEnglish
Pages (from-to)499-508
Number of pages10
JournalBiomaterials Science
Volume11
Issue number2
DOIs
Publication statusPublished - 23 Nov 2022

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