18 GHz electromagnetic field induces permeability of Gram-positive cocci.

Scientific reports · 2015 · Mixed · Low evidence

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MixedLow evidencePaper 4769

Study snapshot

PublicationScientific reports · 2015

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

The effect of electromagnetic field (EMF) exposures at the microwave (MW) frequency of 18 GHz, on four cocci, Planococcus maritimus KMM 3738, Staphylococcus aureus CIP 65.8(T), S. aureus ATCC 25923 and S. epidermidis ATCC 14990(T), was investigated. We demonstrate that exposing the bacteria to an EMF induced permeability in the bacterial membranes of all strains studied, as confirmed directly by transmission electron microscopy (TEM), and indirectly via the propidium iodide assay and the uptake of silica nanospheres. The cells remained permeable for at least nine minutes after EMF exposure. It was shown that all strains internalized 23.5 nm nanospheres, whereas the internalization of the 46.3 nm nanospheres differed amongst the bacterial strains (S. epidermidis ATCC 14990(T) ~ 0%; Staphylococcus aureus CIP 65.8(T) S. aureus ATCC 25923, ~40%; Planococcus maritimus KMM 3738, ~ 80%). Cell viability experiments indicated that up to 84% of the cells exposed to the EMF remained viable. The morphology of the bacterial cells was not altered, as inferred from the scanning electron micrographs, however traces of leaked cytosolic fluids from the EMF exposed cells could be detected. EMF-induced permeabilization may represent an innovative, alternative cell permeability technique for applications in biomedical engineering, cell drug delivery and gene therapy.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typein_vitro

Effect directionmixed

PopulationGram-positive cocci strains: Planococcus maritimus KMM 3738; Staphylococcus aureus CIP 65.8(T); S. aureus ATCC 25923; Staphylococcus epidermidis ATCC 14990(T)

Sample sizeNot supplied

Exposuremicrowave · 18000 MHz

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Exposure to an 18 GHz electromagnetic field induced membrane permeability in all four Gram-positive cocci strains, supported by TEM and by propidium iodide assay and silica nanosphere uptake. Cells remained permeable for at least 9 minutes after exposure; all strains internalized 23.5 nm nanospheres, while 46.3 nm nanosphere internalization varied by strain (~0% to ~80%). Viability testing indicated up to 84% of exposed cells remained viable, and morphology was not altered on SEM, though traces of leaked cytosolic fluids were observed.

Outcomes measured

Bacterial membrane permeability
Propidium iodide uptake (permeability assay)
Uptake/internalization of silica nanospheres (23.5 nm and 46.3 nm)
Cell viability
Cell morphology (TEM/SEM observations)
Cytosolic fluid leakage (SEM)
Duration of post-exposure permeability

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": 18000,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Gram-positive cocci strains: Planococcus maritimus KMM 3738; Staphylococcus aureus CIP 65.8(T); S. aureus ATCC 25923; Staphylococcus epidermidis ATCC 14990(T)",
  "sample_size": null,
  "outcomes": [
    "Bacterial membrane permeability",
    "Propidium iodide uptake (permeability assay)",
    "Uptake/internalization of silica nanospheres (23.5 nm and 46.3 nm)",
    "Cell viability",
    "Cell morphology (TEM/SEM observations)",
    "Cytosolic fluid leakage (SEM)",
    "Duration of post-exposure permeability"
  ],
  "main_findings": "Exposure to an 18 GHz electromagnetic field induced membrane permeability in all four Gram-positive cocci strains, supported by TEM and by propidium iodide assay and silica nanosphere uptake. Cells remained permeable for at least 9 minutes after exposure; all strains internalized 23.5 nm nanospheres, while 46.3 nm nanosphere internalization varied by strain (~0% to ~80%). Viability testing indicated up to 84% of exposed cells remained viable, and morphology was not altered on SEM, though traces of leaked cytosolic fluids were observed.",
  "effect_direction": "mixed",
  "limitations": [],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "18 GHz",
    "microwave",
    "electromagnetic field",
    "bacteria",
    "Gram-positive cocci",
    "membrane permeability",
    "propidium iodide",
    "silica nanospheres",
    "TEM",
    "SEM",
    "viability"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1038/srep10980
PubMed: 26077933

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