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

Direct link
BETA
Publications (10 of 15) Show all publications
Häffner, S. M., Nyström, L., Browning, K. L., Nielsen, H. M., Strömstedt, A. A., van der Plas, M. J. A., . . . Malmsten, M. (2019). Interaction of Laponite with Membrane Components - Consequences for Bacterial Aggregation and Infection Confinement. ACS Applied Materials and Interfaces, 11(17), 15389-15400
Open this publication in new window or tab >>Interaction of Laponite with Membrane Components - Consequences for Bacterial Aggregation and Infection Confinement
Show others...
2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 17, p. 15389-15400Article in journal (Refereed) Published
Abstract [en]

The antimicrobial effects of Laponite nano particles with or without loading of the antimicrobial peptide LL-37 was investigated along with their membrane interactions. The study combines data from ellipsometry, circular dichroism, fluorescence spectroscopy, particle size/zeta potential measurements, and confocal microscopy. As a result of the net negative charge of Laponite, loading of net positively charged LL-37 increases with increasing pH. The peptide was found to bind primarily to the outer surface of the Laponite nanoparticles in a predominantly helical conformation, leading to charge reversal. Despite their net positive charge, peptide-loaded Laponite nanoparticles did not kill Gram-negative Escherichia coli bacteria or disrupt anionic model liposomes. They did however cause bacteria flocculation, originating from the interaction of Laponite and bacterial lipopolysaccharide (LPS). Free LL-37, in contrast, is potently antimicrobial through membrane disruption but does not induce bacterial aggregation in the concentration range investigated. Through LL-37 loading of Laponite nanoparticles, the combined effects of bacterial flocculation and membrane lysis are observed. However, bacteria aggregation seems to be limited to Gram-negative bacteria as Laponite did not cause flocculation of Gram-positive Bacillus subtilis bacteria nor did it bind to lipoteichoic acid from bacterial envelopes. Taken together, the present investigation reports several novel phenomena by demonstrating that nanoparticle charge does not invariably control membrane destabilization and by identifying the ability of anionic Laponite nanoparticles to effectively flocculate Gram-negative bacteria through LPS binding. As demonstrated in cell experiments, such aggregation results in diminished LPS-induced cell activation, thus outlining a promising approach for confinement of infection and inflammation caused by such pathogens.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
Keywords
antimicrobial, bacteria flocculation, infection confinement, Laponite, membrane
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-383840 (URN)10.1021/acsami.9b03527 (DOI)000466988800022 ()30951282 (PubMedID)
Funder
Swedish Research Council, 2016-05157Swedish Research Council, 2017-02341
Available from: 2019-05-27 Created: 2019-05-27 Last updated: 2019-05-27Bibliographically approved
Nordström, R., Nyström, L., Ilyas, H., Atreya, H. S., Borro, B. C. & Malmsten, M. (2019). Microgels as carriers of antimicrobial peptides – effects of peptide PEGylation. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 565, 8-15
Open this publication in new window or tab >>Microgels as carriers of antimicrobial peptides – effects of peptide PEGylation
Show others...
2019 (English)In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 565, p. 8-15Article in journal (Refereed) Published
Abstract [en]

Delivery systems are likely to be central for the translation of antimicrobial peptides (AMPs) towards therapeutics. Addressing AMP interactions with microgel carriers, we here investigate how poly(ethylene glycol) conjugation ('PEGylation') of AMPs affect their loading and release to/from microgels, combining structural studies using nuclear magnetic resonance (NMR) with ellipsometry, circular dichroism spectroscopy (CD), and light scattering. Such studies demonstrate that poly(ethyl acrylate-co-methacrylic acid) microgels bind considerable amounts of the positively charged AMP KYE28 (KYEITTIHNLFRKLTHRLFRRNFGYTLR) and its PEGylated variants KYE28-PEG48, PEG48-KYE28, and PEG24-KYE28-PEG24. Z-potential measurements indicate that KYE28 resides primarily inside the microgel core, and that localization of the PEGylated peptides is shifted towards the microgel corona. Furthermore, while all peptides are disordered in solution, CD measurements report on helix induction on microgel binding, particularly so for the PEGylated peptides. Addressing such conformational changes in more detail, NMR structural studies showed that peptide-microgel interactions are facilitated by a hydrophobic domain formed by the peptide after microgel binding, and with modulating electrostatic/salt bridge interaction between the positively charged peptide residues and negative microgel charges. As the microgels remain negatively charged also at high peptide load, membrane disruption and antimicrobial effects necessitates peptide release, demonstrated to be promoted by PEGylation and high ionic strength. Importantly, microgel loading, as well as peptide localization, conformation, and release, did not depend significantly on PEG conjugation site, but instead seems to be dictated by the PEG content of the peptide conjugates.

Keywords
Antimicrobial peptide, Drug delivery, Microgel, NMR, PEGylation
National Category
Pharmaceutical Sciences
Identifiers
urn:nbn:se:uu:diva-361401 (URN)10.1016/j.colsurfa.2018.12.049 (DOI)000457062300002 ()
Funder
Swedish Research Council, 2012-1842Swedish Research Council, 2015-06720
Available from: 2018-09-24 Created: 2018-09-24 Last updated: 2019-10-12Bibliographically approved
Nyström, L., Al-Rammahi, N., Malekkhaiat Häffner, S., Strömstedt, A. A., Browning, K. L. & Malmsten, M. (2018). Avidin-biotin cross-linked microgel multilayers as carriers for antimicrobial peptides. Biomacromolecules, 19(12), 4691-4702
Open this publication in new window or tab >>Avidin-biotin cross-linked microgel multilayers as carriers for antimicrobial peptides
Show others...
2018 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 12, p. 4691-4702Article in journal (Refereed) Published
Abstract [en]

Herein, we report on the formation of cross-linked antimicrobial peptide-loaded microgel multilayers. Poly(ethyl acrylate- co-methacrylic acid) microgels were synthesized and functionalized with biotin to enable the formation of microgel multilayers cross-linked with avidin. Microgel functionalization and avidin cross-linking were verified with infrared spectroscopy, dynamic light scattering, and z-potential measurements, while multilayer formation (up to four layers) was studied with null ellipsometry and quartz crystal microbalance with dissipation (QCM-D). Incorporation of the antimicrobial peptide KYE28 (KYEITTIHNLFRKLTHRLFRRNFGYTLR) into the microgel multilayers was achieved either in one shot after multilayer formation or through addition after each microgel layer deposition. The latter was found to strongly promote peptide incorporation. Further, antimicrobial properties of the peptide-loaded microgel multilayers against Escherichia coli were investigated and compared to those of a peptide-loaded microgel monolayer. Results showed a more pronounced suppression in bacterial viability in suspension for the microgel multilayers. Correspondingly, LIVE/DEAD staining showed promoted disruption of adhered bacteria for the KYE28-loaded multilayers. Taken together, cross-linked microgel multilayers thus show promise as high load surface coatings for antimicrobial peptides.

National Category
Pharmaceutical Sciences
Research subject
Pharmaceutical Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-361399 (URN)10.1021/acs.biomac.8b01484 (DOI)000453109200018 ()
Funder
Swedish Research Council, 2016-05157
Available from: 2018-09-24 Created: 2018-09-24 Last updated: 2019-01-15Bibliographically approved
Nyström, L. & Malmsten, M. (2018). Membrane interactions and cell selectivity of amphiphilic anticancer peptides. Current Opinion in Colloid & Interface Science, 38, 1-17
Open this publication in new window or tab >>Membrane interactions and cell selectivity of amphiphilic anticancer peptides
2018 (English)In: Current Opinion in Colloid & Interface Science, ISSN 1359-0294, E-ISSN 1879-0399, Vol. 38, p. 1-17Article, review/survey (Refereed) Published
Abstract [en]

Following considerable research efforts on antimicrobial effects by cationic and amphiphilic peptides during the last couple of decades, increasing focus has recently been placed on additional host defense and other biological functions by such peptides, such as anti-inflammatory and anticancer effects. Regarding the latter, it has been increasingly understood that amphiphilic peptides present interesting opportunities not only for reaching selective cancer cell toxicity, but also for promoting uptake of other anticancer therapeutics and of nanopariculate delivery systems containing such drugs. While there is an emerging understanding of the direct antimicrobial function of amphiphilic peptides through bacterial membrane destabilization, the mechanisms underlying their anticancer effects remain less clear. Here, we therefore provide a brief overview on factors affecting toxicity of amphiphilic peptides against tumor and non-malignant cells, and also describe how such peptides can be combined with conjugation moieties or drug delivery systems for increased anticancer effects.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE LONDON, 2018
Keywords
Amphiphilic, Anticancer, Antimicrobial peptide, Membrane
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-374869 (URN)10.1016/j.cocis.2018.06.009 (DOI)000455063600002 ()
Funder
Swedish Research Council, 2016-05157
Available from: 2019-01-31 Created: 2019-01-31 Last updated: 2019-01-31Bibliographically approved
Nordström, R., Nyström, L., Andren, O. C. J., Malkoch, M., Umerska, A., Davoudi, M., . . . Malmsten, M. (2018). Membrane interactions of microgels as carriers of antimicrobial peptides. Journal of Colloid and Interface Science, 513, 141-150
Open this publication in new window or tab >>Membrane interactions of microgels as carriers of antimicrobial peptides
Show others...
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
Keywords
Antimicrobial peptide, Drug delivery, Lipid membrane, Microgel
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-351759 (URN)10.1016/j.jcis.2017.11.014 (DOI)000428834900015 ()29145017 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 604182
Available from: 2018-05-31 Created: 2018-05-31 Last updated: 2019-10-12Bibliographically approved
Nyström, L. (2018). Microgels as Carriers for Antimicrobial Peptides: Surface-bound microgels, and factors affecting peptide interactions. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
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
Nyström, L., Strömstedt, A. A., Schmidtchen, A. & Malmsten, M. (2018). Peptide-Loaded Microgels as Antimicrobial and Anti-Inflammatory Surface Coatings. Biomacromolecules, 19(8), 3456-3466
Open this publication in new window or tab >>Peptide-Loaded Microgels as Antimicrobial and Anti-Inflammatory Surface Coatings
2018 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 8, p. 3456-3466Article in journal (Refereed) Published
Abstract [en]

Here we report on covalently immobilized poly(ethyl acrylate- co-methacrylic acid) microgels loaded with the host defense peptide KYE28 (KYEITTIHNLFRKLTHRLFRRNFGYTLR), which is derived from human heparin cofactor II, as well as its poly(ethylene glycol)-conjugated (PEGylated) version, KYE28PEG. Peptide loading and release, as well as the consequences of these processes on the microgel and peptide properties, were studied by in situ ellipsometry, confocal microscopy, zeta potential measurements, and circular dichroism spectroscopy. The results show that the microgel-peptide interactions are electrostatically dominated, thus promoted at higher microgel charge density, while PEGylation suppresses peptide binding. PEGylation also enhances the α-helix induction observed for KYE28 upon microgel incorporation. Additionally, peptide release is facilitated at physiological salt concentration, particularly so for KYE28PEG, which illustrates the importance of electrostatic interactions. In vitro studies on Escherichia coli show that the microgel-modified surfaces display potent antifouling properties in both the absence and presence of the incorporated peptide. While contact killing dominates at low ionic strength for the peptide-loaded microgels, released peptides also provide antimicrobial activity in bulk at a high ionic strength. Additionally, KYE28- and KYE28PEG-loaded microgels display anti-inflammatory effects on human monocytes. Taken together, these results not only show that surface-bound microgels offer an interesting approach for local drug delivery of host defense peptides but also illustrate the need to achieve high surface loads of peptides for efficient biological effects.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Pharmacology and Toxicology Biomaterials Science
Identifiers
urn:nbn:se:uu:diva-358186 (URN)10.1021/acs.biomac.8b00776 (DOI)000441852400029 ()29976055 (PubMedID)
Funder
Swedish Research Council, 2016-05157 2017-02341
Available from: 2018-08-24 Created: 2018-08-24 Last updated: 2018-11-06Bibliographically approved
Nyström, L., Nordström, R., Strömstedt, A. A., Saunders, B., Alvarez-Asencio, R., Rutland, M. & Malmsten, M. (2018). Peptide-loaded microgels as antimicrobial surface coatings. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Peptide-loaded microgels as antimicrobial surface coatings
Show others...
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-367230 (URN)000435539907572 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2018-12-06Bibliographically approved
Nyström, L., Nordström, R., Bramhill, J., Saunders, B., Alvarez-Asencio, R., Rutland, M. & Malmsten, M. (2018). Peptide-loaded microgels as carriers of antimicrobial peptides. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Peptide-loaded microgels as carriers of antimicrobial peptides
Show others...
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-367231 (URN)000435539907125 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2018-12-06Bibliographically approved
Nordström, R., Nyström, L., Andren, O., Malkoch, M., Umerska, A., Davoudi, M., . . . Malmsten, M. (2018). Poly(acrylic acid) microgels as carriers for antimicrobial peptides. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, USA.. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>Poly(acrylic acid) microgels as carriers for antimicrobial peptides
Show others...
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Washington, D.C.: American Chemical Society (ACS), 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-368929 (URN)000435539907574 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, USA.
Note

Meeting Abstract: 797

Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5236-9107

Search in DiVA

Show all publications