Degradable dendritic nanogels as carriers for antimicrobial peptides

Research output: Contribution to journalArticle

Abstract

In the present study, we investigate degradable anionic dendritic nanogels (DNG) as carriers for antimicrobial peptides (AMPs). In such systems, the dendritic part contains carboxylic acid-based anionic binding sites for cationic AMPs, whereas linear poly(ethylene glycol) (PEG) chains form a shell for promotion of biological stealth. In order to clarify factors influencing membrane interactions of such systems, we here address effects of nanogel charge, cross-linking, and degradation on peptide loading/release, as well as consequences of these factors for lipid membrane interactions and antimicrobial effects. The DNGs were found to bind the AMPs LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) and DPK-060 (GKHKNKGKKNGKHNGWKWWW). For the smaller DPK-060 peptide, loading was found to increase with increasing nanogel charge density. For the larger LL-37, on the other hand, peptide loading was largely insensitive to nanogel charge density. In line with this, results on the secondary structure, as well as on the absence of stabilization from proteolytic degradation by the nanogels, show that the larger LL-37 is unable to enter into the interior of the nanogels. While 40–60% nanogel degradation occurred over 10 days, promoted at high ionic strength and lower cross-linking density/higher anionic charge content, peptide release at physiological ionic strength was substantially faster, and membrane destabilization not relying on nanogel degradation. Ellipsometry and liposome leakage experiments showed both free peptide and peptide/DNG complexes to cause membrane destabilization, indicated also by antimicrobial activities being comparable for nanogel-bound and free peptide. Finally, the DNGs were demonstrated to display low toxicity towards erythrocytes even at peptide concentrations of 100 µM.

Details

Authors
Organisations
External organisations
  • Uppsala University
  • KTH Royal Institute of Technology
  • University of Copenhagen
  • Bispebjerg Hospital
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Pharmaceutical Sciences
  • Biochemistry and Molecular Biology

Keywords

  • Antimicrobial peptide, Degradable, Dendritic, Hyperbranched drug delivery, Membrane, Nanogel
Original languageEnglish
Pages (from-to)592-602
Number of pages11
JournalJournal of Colloid and Interface Science
Volume554
Publication statusPublished - 2019 Oct 15
Publication categoryResearch
Peer-reviewedYes