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

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.

AI evidence extraction

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.

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

{
    "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": 0.7399999999999999911182158029987476766109466552734375,
    "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": []
}

Comments

Log in to comment.

No comments yet.