uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Membrane interactions of microgels as carriers of antimicrobial peptides
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.ORCID iD: 0000-0001-5626-3959
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.ORCID iD: 0000-0001-5236-9107
Royal Inst Technol, Dept Fibre & Polymer Technol, SE-10044 Stockholm, Sweden..
Royal Inst Technol, Dept Fibre & Polymer Technol, SE-10044 Stockholm, Sweden..
Show others and affiliations
2018 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 513, p. 141-150Article in journal (Refereed) Published
Abstract [en]

Microgels are interesting as potential delivery systems for antimicrobial peptides. In order to elucidate membrane interactions of such systems, we here investigate effects of microgel charge density on antimicrobial peptide loading and release, as well as consequences of this for membrane interactions and antimicrobial effects, using ellipsometry, circular dichroism spectroscopy, nanoparticle tracking analysis, dynamic light scattering and z-potential measurements. Anionic poly(ethyl acrylate-co-methacrylic acid) microgels were found to incorporate considerable amounts of the cationic antimicrobial peptides LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) and DPK-060 (GKHKNKGKKNGKHNGWKWWW) and to protect incorporated peptides from degradation by infection-related proteases at high microgel charge density. As a result of their net negative z-potential also at high peptide loading, neither empty nor peptide-loaded microgels adsorb at supported bacteria-mimicking membranes. Instead, membrane disruption is mediated almost exclusively by peptide release. Mirroring this, antimicrobial effects against several clinically relevant bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa) were found to be promoted by factors facilitating peptide release, such as decreasing peptide length and decreasing microgel charge density. Microgels were further demonstrated to display low toxicity towards erythrocytes. Taken together, the results demonstrate some interesting opportunities for the use of microgels as delivery systems for antimicrobial peptides, but also highlight several key factors which need to be controlled for their successful use.

Place, publisher, year, edition, pages
ACADEMIC PRESS INC ELSEVIER SCIENCE , 2018. Vol. 513, p. 141-150
Keywords [en]
Antimicrobial peptide, Drug delivery, Lipid membrane, Microgel
National Category
Physical Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-351759DOI: 10.1016/j.jcis.2017.11.014ISI: 000428834900015PubMedID: 29145017OAI: oai:DiVA.org:uu-351759DiVA, id: diva2:1211837
Funder
EU, FP7, Seventh Framework Programme, 604182Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2019-10-12Bibliographically approved
In thesis
1. Microgels as Carriers for Antimicrobial Peptides: Surface-bound microgels, and factors affecting peptide interactions
Open this publication in new window or tab >>Microgels as Carriers for Antimicrobial Peptides: Surface-bound microgels, and factors affecting peptide interactions
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

With a growing number of multi-resistant bacteria against conventional antibiotics, there is an urgent need to identify new antimicrobial therapeutics. One example that has gained considerable interest is antimicrobial peptides (AMPs). For AMPs to reach their full potential as therapeutics, as well as for other peptide and protein drugs, the right drug delivery system may overcome reported shortcomings, such as fast clearance in the bloodstream and proteolytic degradation. Microgels are weakly cross-linked polymer colloids, which can be made responsive to various stimuli. In the context of drug delivery, microgels are of particular interest as carriers for biomacromolecular drugs, such as peptides and proteins, as their water-rich environment offers both protection against enzymatic degradation and triggered release possibilities. Combining these, the aim of this thesis was to investigate electrostatically triggered surface-bound microgels as a delivery system for AMPs, as well as evaluate such systems as an antimicrobial and anti-inflammatory coating for biomaterials.

Results presented in this thesis demonstrate effects of microgel charge density, pH, and ionic strength on microgel volume transitions at solid interfaces, surface-induced microgel deformation and nanomechanical properties. In addition, effects of both microgel properties (charge density) and peptide properties (molecular weight, charge density, and posttranslational modifications) on peptide loading and release from surface-bound microgels were investigated. The presented thesis also reports in vitro studies of AMP-loaded microgels in dispersion and surface-bound, as either mono- or multilayers. Notably, the interplay between surface- and release-related effects for the antimicrobial properties of AMP-loaded microgels are investigated. In addition, anti-inflammatory properties of AMP-loaded microgels are also reported.

Taken together, microgels prove an interesting and versatile drug delivery system for AMPs. Results obtained in this thesis have demonstrated that several key factors need to be taken into consideration in the development of surface-bound microgels as a carrier for AMPs, and that small changes in microgel and peptide properties can alter peptide loading and release profiles.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 66
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 259
Keywords
Antimicrobial peptides, Biomaterial coating, Drug delivery, Host defence peptides, Microgels, pH-responsive, Surface-bound
National Category
Pharmaceutical Sciences Biomaterials Science Physical Chemistry
Research subject
Pharmaceutical Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-360241 (URN)978-91-513-0473-1 (ISBN)
Public defence
2018-11-30, A1:111a, BMC, Husargatan 3, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2018-11-09 Created: 2018-10-12 Last updated: 2018-11-19
2. Polymeric Nanoparticles as Carriers for Antimicrobial Peptides: Factors Affecting Peptide and Membrane Interactions
Open this publication in new window or tab >>Polymeric Nanoparticles as Carriers for Antimicrobial Peptides: Factors Affecting Peptide and Membrane Interactions
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

As resistance towards conventional antibiotics is becoming more pronounced, cationic antimicrobial peptides (AMPs) have received considerable attention as possible therapeutic alternatives. Thousands of potent AMPs occur in humans, animals, plants and fungi as a natural part of the immune system. However, there are several challenges with AMP therapeutics related to formulation and delivery. Examples include proteolytic sensitivity and serum protein binding, resulting in quick degradation, loss of activity and clearance. Therefore, it is important to find a suitable drug delivery system to meet these protection and delivery challenges. Micro-/nanogels are loosely crosslinked polymer colloids with high water content that can be made to trigger at a wide range of stimuli. They have shown promise as delivery systems for AMPs, as the aqueous environment they create allows the peptides to maintain their natural conformation, while their gel networks offer protection and triggered release. This thesis aims towards expanding the knowledge about degradable and non-degradable pH-responsive micro-/nanogels as carriers for AMPs.

The results in this thesis show that factors relating to the drug delivery system (degradability, charge and crosslinker density), the surrounding media (pH and ionic strength) and the peptide properties (length, charge, PEGylation) all affect the peptide loading to, protection, release from and effect of AMP-loaded gels. Studies of the interaction of AMP-loaded microgels with bacteria-modelling liposomes and lipid bilayers have verified peptide effect after gel incorporation, as further demonstrated by in vitro studies on several bacterial strains. Neutron reflectometry provided detailed mechanistic information on the interaction between AMP-loaded gels and bacteria-modelling lipid bilayers, showing that the antimicrobial unit is the released peptide. All gels showed low, promising hemolysis and some gels could offer protection against proteolytic degradation of AMPs.

In summary, non-degradable and degradable micro-/nanogels are versatile and interesting candidates as AMP carriers. Small changes in the gel composition or the AMP used can dramatically change the peptide loading, release and effect. It is therefore necessary to carefully consider and evaluate the optimal carrier for every AMP and the application at hand.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 74
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 280
Keywords
antimicrobial peptide, microgel, degradable, nanogel, drug delivery, PEGylation, secondary structure, model membrane, lipid bilayer, neutron reflectometry, ellipsometry
National Category
Pharmaceutical Sciences Physical Chemistry
Research subject
Pharmaceutical Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-383639 (URN)978-91-513-0778-7 (ISBN)
Public defence
2019-11-29, Room A1:107a, BMC, Husargatan 3, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2019-11-07 Created: 2019-10-12 Last updated: 2019-11-27

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textPubMed

Authority records BETA

Nordström, RandiNyström, LinaMalmsten, M

Search in DiVA

By author/editor
Nordström, RandiNyström, LinaMalmsten, M
By organisation
Department of Pharmacy
In the same journal
Journal of Colloid and Interface Science
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 94 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf