Effect of 2.45 GHz microwave radiation on permeability of unilamellar liposomes to 5(6)-carboxyfluorescein. Evidence of non-thermal leakage.

Biochimica et biophysica acta · 1991 · Harm · Low evidence

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HarmLow evidencePaper 6283

After 10 minutes of exposure, microwave-exposed liposome samples showed a significant increase in permeability (carboxyfluorescein release) compared with samples exposed to heat alone. The effect was observed above the lipid membrane phase transition temperat…

Study snapshot

PublicationBiochimica et biophysica acta · 1991

Study typein_vitro

Reported directionHarm

Evidence ratingLow

Abstract

The influence of 2.45 GHz microwave radiation on the membrane permeability of unilamellar liposomes was studied using the marker 5(6)-carboxyfluorescein trapped in phosphatidylcholine liposomes. The release of the fluorescent marker was followed by spectrofluorimetry after an exposure of 10 minutes to either microwave radiation or to heat alone of the liposome solutions. A significant increase of the permeability of carboxyfluorescein through the membrane was observed for the microwave-exposed samples compared to those exposed to normal heating only. Exposure to 2.45 GHz microwave radiation of liposomes has been previously found to produce increased membrane permeability as compared with heating. However, in contrast to previous studies, the observations reported here were made above the phase transition temperature of the lipid membrane. The experimental setup included monitoring of the temperature during microwave exposure simultaneously at several points in the solution volume using a fiberoptic thermometer. Possible mechanisms to explain the observations are discussed.

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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 directionharm

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave · 2450 MHz · 10 minutes

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Outcomes measured

Membrane permeability of unilamellar phosphatidylcholine liposomes
Release/leakage of 5(6)-carboxyfluorescein (fluorescent marker) measured by spectrofluorimetry

Limitations

No sample size reported in the abstract
Specific exposure metrics beyond frequency and duration (e.g., power density/SAR) not reported in the abstract
In vitro liposome model; relevance to living organisms not addressed in the abstract

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": 2450,
    "sar_wkg": null,
    "duration": "10 minutes"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Membrane permeability of unilamellar phosphatidylcholine liposomes",
    "Release/leakage of 5(6)-carboxyfluorescein (fluorescent marker) measured by spectrofluorimetry"
  ],
  "main_findings": "After 10 minutes of exposure, microwave-exposed liposome samples showed a significant increase in permeability (carboxyfluorescein release) compared with samples exposed to heat alone. The effect was observed above the lipid membrane phase transition temperature, with temperature monitored at several points during microwave exposure using a fiberoptic thermometer.",
  "effect_direction": "harm",
  "limitations": [
    "No sample size reported in the abstract",
    "Specific exposure metrics beyond frequency and duration (e.g., power density/SAR) not reported in the abstract",
    "In vitro liposome model; relevance to living organisms not addressed in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "2.45 GHz",
    "microwave radiation",
    "liposomes",
    "membrane permeability",
    "carboxyfluorescein",
    "non-thermal leakage",
    "spectrofluorimetry",
    "temperature monitoring",
    "phase transition temperature"
  ],
  "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: 10.1016/0005-2736(91)90418-8
PubMed: 2025632

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