Effects of industrial, scientific, and medical (ISM) band frequency 2.45 GHz on membrane integrity and oxidative stress of human skin bacteria

Abstract

Purpose: To investigate the effects of 2.45 GHz radiofrequency radiation (RFR) on oxidative stress and membrane integrity of human skin bacteria. Materials and methods: Cultures of Staphylococcus epidermidis, Micrococcus luteus, and Enterobacter cloacae were exposed to 2.45 GHz RFR. Oxidative stress was assessed by quantifying hydroxyl (•OH) and superoxide (O2•-) radicals and total intracellular ROS (DCFH2-DA assay). Lipid peroxidation (MDA levels) and protein carbonyl content were measured as oxidative damage markers. Membrane integrity was examined by SEM and TEM imaging and by evaluating protein and carbohydrate leakage. All experiments were performed with at least three independent biological replicates. Results: RFR-exposed bacteria exhibited a marked increase in ROS generation compared to sham and control groups. Total intracellular ROS, hydroxyl radicals, and superoxide radicals were significantly elevated (∼ 2 fold), indicating strong oxidative stress induction. This biochemical stress correlated with structural alterations: SEM and TEM revealed disrupted cell membranes and cytoplasmic disorganization. Functionally, exposed bacteria showed enhanced membrane permeability, evidenced by substantial leakage of proteins and carbohydrates into the extracellular environment. Furthermore, oxidative damage was confirmed biochemically, with significantly elevated malondialdehyde (MDA >1.5 fold) levels reflecting lipid peroxidation, and increased protein carbonyl (>2 fold) content indicating oxidative modification of proteins. These effects were consistent across all three bacterial species, although E. cloacae demonstrated more pronounced damages. Collectively, these findings highlight a clear link between RFR-induced ROS overproduction, oxidative macromolecular damage, and compromised cellular integrity. Conclusions: Exposure to 2.45 GHz RFR induces oxidative stress, membrane disruption, and macromolecular leakage in skin-associated bacteria, suggesting possible risks to skin microbiome stability under high-RFR environments.

AI evidence extraction

Main findings

Bacterial cultures exposed to 2.45 GHz RFR showed significantly increased ROS generation (~2-fold increases in total intracellular ROS, hydroxyl radicals, and superoxide radicals) versus sham/control. SEM/TEM indicated disrupted membranes and cytoplasmic disorganization, accompanied by increased protein/carbohydrate leakage and elevated oxidative damage markers (MDA >1.5-fold; protein carbonyl >2-fold), with effects reported across all three species and more pronounced damage in E. cloacae.

Outcomes measured

• Total intracellular ROS (DCFH2-DA assay)
• Hydroxyl radicals (•OH)
• Superoxide radicals (O2•-)
• Lipid peroxidation (MDA levels)
• Protein carbonyl content
• Membrane integrity (SEM/TEM)
• Membrane permeability (protein leakage, carbohydrate leakage)

Limitations

• Exposure metrics such as SAR and exposure duration were not reported in the abstract.
• In vitro bacterial culture study; findings may not directly translate to in vivo human skin microbiome conditions.
• Sample size per condition not specified beyond at least three independent biological replicates.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "RF",
        "source": "ISM band (2.45 GHz) radiofrequency radiation",
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Human skin-associated bacteria cultures (Staphylococcus epidermidis, Micrococcus luteus, Enterobacter cloacae)",
    "sample_size": null,
    "outcomes": [
        "Total intracellular ROS (DCFH2-DA assay)",
        "Hydroxyl radicals (•OH)",
        "Superoxide radicals (O2•-)",
        "Lipid peroxidation (MDA levels)",
        "Protein carbonyl content",
        "Membrane integrity (SEM/TEM)",
        "Membrane permeability (protein leakage, carbohydrate leakage)"
    ],
    "main_findings": "Bacterial cultures exposed to 2.45 GHz RFR showed significantly increased ROS generation (~2-fold increases in total intracellular ROS, hydroxyl radicals, and superoxide radicals) versus sham/control. SEM/TEM indicated disrupted membranes and cytoplasmic disorganization, accompanied by increased protein/carbohydrate leakage and elevated oxidative damage markers (MDA >1.5-fold; protein carbonyl >2-fold), with effects reported across all three species and more pronounced damage in E. cloacae.",
    "effect_direction": "harm",
    "limitations": [
        "Exposure metrics such as SAR and exposure duration were not reported in the abstract.",
        "In vitro bacterial culture study; findings may not directly translate to in vivo human skin microbiome conditions.",
        "Sample size per condition not specified beyond at least three independent biological replicates."
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "2.45 GHz",
        "radiofrequency radiation",
        "ISM band",
        "skin microbiome",
        "Staphylococcus epidermidis",
        "Micrococcus luteus",
        "Enterobacter cloacae",
        "oxidative stress",
        "ROS",
        "membrane integrity",
        "lipid peroxidation",
        "protein carbonyl",
        "SEM",
        "TEM"
    ],
    "suggested_hubs": []
}

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