Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement

Sara Malekkhaiat Häffner; Lina Nyström; Kathryn L Browning; Hanne Mörck Nielsen; Adam A Strömstedt; Mariena J A van der Plas; Artur Schmidtchen; Martin Malmsten

doi:10.1021/acsami.9b03527

Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement

Sara Malekkhaiat Häffner, Lina Nyström, Kathryn L Browning, Hanne Mörck Nielsen, Adam A Strömstedt, Mariena J A van der Plas, Artur Schmidtchen, Martin Malmsten

Department of Biomedical Sciences

9 Citations (Scopus)

Abstract

The antimicrobial effects of Laponite nanoparticles 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/ζ 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.

Original language	English
Journal	A C S Applied Materials and Interfaces
Volume	11
Issue number	17
Pages (from-to)	15389-15400
Number of pages	12
ISSN	1944-8244
DOIs	https://doi.org/10.1021/acsami.9b03527
Publication status	Published - 1 May 2019

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Malekkhaiat Häffner, S., Nyström, L., Browning, K. L., Mörck Nielsen, H., Strömstedt, A. A., van der Plas, M. J. A., Schmidtchen, A., & Malmsten, M. (2019). Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement. A C S Applied Materials and Interfaces, 11(17), 15389-15400. https://doi.org/10.1021/acsami.9b03527

Malekkhaiat Häffner, S, Nyström, L, Browning, KL , Mörck Nielsen, H, Strömstedt, AA, van der Plas, MJA, Schmidtchen, A & Malmsten, M 2019, 'Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement', A C S Applied Materials and Interfaces, vol. 11, no. 17, pp. 15389-15400. https://doi.org/10.1021/acsami.9b03527

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title = "Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement",

abstract = "The antimicrobial effects of Laponite nanoparticles 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/ζ 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.",

author = "{Malekkhaiat H{\"a}ffner}, Sara and Lina Nystr{\"o}m and Browning, {Kathryn L} and {M{\"o}rck Nielsen}, Hanne and Str{\"o}mstedt, {Adam A} and {van der Plas}, {Mariena J A} and Artur Schmidtchen and Martin Malmsten",

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T1 - Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement

AU - Malekkhaiat Häffner, Sara

AU - Nyström, Lina

AU - Browning, Kathryn L

AU - Mörck Nielsen, Hanne

AU - Strömstedt, Adam A

AU - van der Plas, Mariena J A

AU - Schmidtchen, Artur

AU - Malmsten, Martin

PY - 2019/5/1

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N2 - The antimicrobial effects of Laponite nanoparticles 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/ζ 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.

AB - The antimicrobial effects of Laponite nanoparticles 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/ζ 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.

U2 - 10.1021/acsami.9b03527

DO - 10.1021/acsami.9b03527

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SN - 1944-8244

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JO - A C S Applied Materials and Interfaces

JF - A C S Applied Materials and Interfaces

IS - 17

ER -

Interaction of Laponite with Membrane Components-Consequences for Bacterial Aggregation and Infection Confinement

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