Enhancement Effect of Static Magnetic Field on Bactericidal Activity

Abstract

Category: Microbiology Tags: static magnetic field, bactericidal activity, nanoparticles, reactive oxygen species, Escherichia coli, Staphylococcus aureus, electromagnetic field safety DOI: 10.1002/smll.202412334 URL: pubmed.ncbi.nlm.nih.gov Overview The biological effects of magnetic fields are pervasive in microorganisms, with significant attention given to alternating magnetic fields (AMFs). However, AMFs induce electrical and magnetothermal effects, which complicate the interpretation of magnetic field-induced biological effects and introduce uncertainties regarding cytotoxicity in practical applications. Key Findings - The static magnetic field (SMF), with few variables and high biocompatibility, presents a promising alternative both for understanding biological mechanisms and ensuring safety in application. However, SMF has shown weak interactions with microorganisms alone. - This study demonstrates that combining SMF with paramagnetic calcium-polypyrrole nanoparticles (Ca-PPy) remarkably enhances bactericidal activity. - Experiments show the synergistic action of SMF and Ca-PPy significantly promotes the generation of reactive oxygen species (ROS), such as singlet oxygen and superoxide anion radicals, in Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). - The synergistic treatment leads to physical disruption of bacterial membranes and achieves an extraordinary bactericidal rate exceeding 94%. - Computational analyses reveal that introducing magnetic fields increases the singlet-to-triplet transition of radical pairs. Conclusion These findings offer new insights into the biological effects of magnetic fields and pave the way for safe and highly effective use of magnetic fields in bactericidal applications. Importantly, the research adds to the growing body of evidence connecting electromagnetic fields to significant biological impacts, including health and safety considerations.

AI evidence extraction

Main findings

The study reports that combining a static magnetic field (SMF) with paramagnetic calcium-polypyrrole nanoparticles (Ca-PPy) markedly enhances bactericidal activity against E. coli and S. aureus, with a reported bactericidal rate exceeding 94%. The synergistic treatment is associated with increased ROS generation (including singlet oxygen and superoxide anion radicals) and physical disruption of bacterial membranes; computational analyses suggest magnetic fields increase singlet-to-triplet transition of radical pairs.

Outcomes measured

• bactericidal activity/bacterial killing rate
• reactive oxygen species (ROS) generation (singlet oxygen, superoxide anion radicals)
• bacterial membrane disruption
• radical pair singlet-to-triplet transition (computational)

Limitations

• No SMF exposure parameters provided (e.g., field strength, exposure duration).
• No sample sizes or statistical details provided in the abstract.
• Findings are in vitro in bacteria; relevance to human health outcomes is not addressed in the abstract.
• Intervention includes nanoparticles (Ca-PPy) in addition to SMF, complicating attribution to SMF alone.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "static",
        "source": "static magnetic field (SMF) combined with paramagnetic calcium-polypyrrole nanoparticles (Ca-PPy)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "bactericidal activity/bacterial killing rate",
        "reactive oxygen species (ROS) generation (singlet oxygen, superoxide anion radicals)",
        "bacterial membrane disruption",
        "radical pair singlet-to-triplet transition (computational)"
    ],
    "main_findings": "The study reports that combining a static magnetic field (SMF) with paramagnetic calcium-polypyrrole nanoparticles (Ca-PPy) markedly enhances bactericidal activity against E. coli and S. aureus, with a reported bactericidal rate exceeding 94%. The synergistic treatment is associated with increased ROS generation (including singlet oxygen and superoxide anion radicals) and physical disruption of bacterial membranes; computational analyses suggest magnetic fields increase singlet-to-triplet transition of radical pairs.",
    "effect_direction": "benefit",
    "limitations": [
        "No SMF exposure parameters provided (e.g., field strength, exposure duration).",
        "No sample sizes or statistical details provided in the abstract.",
        "Findings are in vitro in bacteria; relevance to human health outcomes is not addressed in the abstract.",
        "Intervention includes nanoparticles (Ca-PPy) in addition to SMF, complicating attribution to SMF alone."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "static magnetic field",
        "SMF",
        "bactericidal activity",
        "nanoparticles",
        "calcium-polypyrrole",
        "Ca-PPy",
        "reactive oxygen species",
        "singlet oxygen",
        "superoxide",
        "Escherichia coli",
        "Staphylococcus aureus",
        "membrane disruption",
        "radical pair mechanism"
    ],
    "suggested_hubs": []
}

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