Uptake of nanoparticles from sunscreen physical filters into cells from increased environmental microwave radiation: increased potential risk of use of sunscreens to human health

2022 · Harm · Low evidence

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HarmLow evidencePaper 760

Study snapshot

Publicationmanual · 2022

Study typein_vitro

Reported directionHarm

Evidence ratingLow

Abstract

Uptake of nanoparticles from sunscreen physical filters into cells from increased environmental microwave radiation: increased potential risk of use of sunscreens to human health Horikoshi, S., Iwabuchi, M., Kawaguchi, M. et al. Uptake of nanoparticles from sunscreen physical filters into cells arising from increased environmental microwave radiation: increased potential risk of the use of sunscreens to human health. Photochem Photobiol Sci (2022). doi.org. Abstract This study examines the microwave chemical risks posed by photocatalysts present in sunscreens (physical filters) against the increasing use of microwaves (radio waves) in the environment, sometimes referred to as electronic smog. Specifically, the study assesses the damage caused by silica-coated physical filters (photocatalysts, TiO2⋅ and/or ZnO) contained in commercially available sunscreens and fresh silica-coated ZnO for sunscreens to mouse skin fibroblasts cells (NIH/3T3) evaluated in vitro by the life/death of cells using two types of electromagnetic waves: UV light and microwave radiation, and under simultaneous irradiation with both UV light and microwaves. Conditions of the electromagnetic waves were such as to be of lower light irradiance than that of UVA/UVB radiation from incident sunlight, and with microwaves near the threshold power levels that affect human health. The photocatalytic activity of the physical filters was investigated by examining the degradation of the rhodamine B (RhB) dye in aqueous media and by the damage caused to DNA plasmids from E. coli. Compared to the photocatalytic activity of ZnO and TiO2 when irradiated with UV light alone, a clear enhanced photocatalytic activity was confirmed upon irradiating these physical filters concurrently with UV and microwaves. Moreover, the uptake of these metal oxides into the NIH/3T3 cells led to the death of these cells as a result of the enhanced photocatalytic activity of the metal oxides on exposure to microwave radiation. Concluding Remarks This study has demonstrated that the degradation of RhB and the degradation of DNA plasmids were promoted by two types of metal-oxide physical filters (ZnO and/or TiO2) in sunscreens when exposed to both UV and microwave radiations, with the irradiation output of the microwaves adjusted to a value close to the legal regulations. The effect of these photoactive filters on NIH/3T3 cells was also examined. In addition to the decomposition of the dye and the damage caused to the DNA plasmids by these photocatalytically active metal oxides, the study has also shown that nanoparticles of these physical filters are taken up by the cells under concurrent irradiation with ultraviolet rays and microwaves. Although we did not discuss the risks to people on using sunscreens (however, see ref. [6]) and the effects of microwaves to human health, we hasten to point out that various catalytic reactions have been shown to be accelerated in Microwave Chemistry [29] as a result of the electromagnetic wave effects. The issue raised in this study is that if ZnO and/or TiO2 contained in cosmetics acted as photocatalysts under UV and UV/MW irradiation, in addition to scattering UV light (as suggested by many), any increase of the microwave intensity in the environment would certainly pose an increased risk to human health as evidenced by the damage caused to DNA plasmids. In addition, to the extent that the presence of metal oxides used as physical filters in sunscreens are activated by the UVA/UVB radiation (320–400 nm/290–320 nm), their simultaneous exposure to microwave radiation can also lead to or otherwise increase their uptake by the cells, a consequence of which can also pose potential risks to human health. link.springer.com

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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

PopulationMouse skin fibroblast cells (NIH/3T3) in vitro; E. coli DNA plasmids in vitro

Sample sizeNot supplied

Exposuremicrowave

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

The study reports enhanced photocatalytic activity of ZnO and/or TiO2 physical filters when exposed to concurrent UV and microwave irradiation compared with UV alone, assessed via rhodamine B degradation and DNA plasmid damage. It also reports uptake of these metal-oxide nanoparticles into NIH/3T3 cells under concurrent UV and microwave exposure, with associated cell death attributed to enhanced photocatalytic activity.

Outcomes measured

Cell viability (life/death) in NIH/3T3 cells
Photocatalytic degradation of rhodamine B dye
Damage to DNA plasmids (E. coli)
Uptake of ZnO/TiO2 nanoparticles into cells under irradiation

Limitations

In vitro study using mouse fibroblast cells and isolated DNA plasmids; findings may not translate to human real-world exposure.
Microwave frequency, exposure duration, and quantitative dosimetry (e.g., SAR) are not provided in the abstract.
No sample sizes or statistical details are reported in the abstract.
Study focuses on photocatalyst-containing sunscreen filters and does not directly assess health outcomes in people.

View raw extracted JSON

{
  "publication_year": 2022,
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": "environmental microwave radiation",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Mouse skin fibroblast cells (NIH/3T3) in vitro; E. coli DNA plasmids in vitro",
  "sample_size": null,
  "outcomes": [
    "Cell viability (life/death) in NIH/3T3 cells",
    "Photocatalytic degradation of rhodamine B dye",
    "Damage to DNA plasmids (E. coli)",
    "Uptake of ZnO/TiO2 nanoparticles into cells under irradiation"
  ],
  "main_findings": "The study reports enhanced photocatalytic activity of ZnO and/or TiO2 physical filters when exposed to concurrent UV and microwave irradiation compared with UV alone, assessed via rhodamine B degradation and DNA plasmid damage. It also reports uptake of these metal-oxide nanoparticles into NIH/3T3 cells under concurrent UV and microwave exposure, with associated cell death attributed to enhanced photocatalytic activity.",
  "effect_direction": "harm",
  "limitations": [
    "In vitro study using mouse fibroblast cells and isolated DNA plasmids; findings may not translate to human real-world exposure.",
    "Microwave frequency, exposure duration, and quantitative dosimetry (e.g., SAR) are not provided in the abstract.",
    "No sample sizes or statistical details are reported in the abstract.",
    "Study focuses on photocatalyst-containing sunscreen filters and does not directly assess health outcomes in people."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "stance": "concern",
  "stance_confidence": 0.78,
  "summary": "This in vitro study evaluated silica-coated ZnO and/or TiO2 sunscreen physical filters under UV, microwave, and combined UV+microwave irradiation. It reports that combined UV+microwave exposure enhanced photocatalytic activity versus UV alone, with increased rhodamine B degradation and DNA plasmid damage. The authors also report nanoparticle uptake into NIH/3T3 cells under concurrent irradiation and associated cell death, framing this as a potential increased health risk with higher environmental microwave intensity.",
  "key_points": [
    "Assessed ZnO and/or TiO2 physical filters from commercial sunscreens and fresh silica-coated ZnO in vitro.",
    "Compared effects of UV alone, microwaves alone, and simultaneous UV+microwave irradiation.",
    "Reported enhanced photocatalytic activity under UV+microwave conditions using rhodamine B dye degradation.",
    "Reported increased damage to E. coli DNA plasmids under UV+microwave exposure.",
    "Reported uptake of metal-oxide nanoparticles into NIH/3T3 cells under concurrent UV and microwave irradiation.",
    "Reported NIH/3T3 cell death associated with nanoparticle uptake and enhanced photocatalytic activity.",
    "Microwave output was described as adjusted close to legal regulatory levels, but specific dosimetry was not provided in the abstract."
  ],
  "categories": [
    "In Vitro",
    "Microwave/RF Exposure",
    "Nanoparticles",
    "Mechanisms (Oxidative/Photocatalytic)"
  ],
  "tags": [
    "Microwave Radiation",
    "UV Radiation",
    "Sunscreen Filters",
    "Titanium Dioxide",
    "Zinc Oxide",
    "Nanoparticles",
    "Photocatalysis",
    "Rhodamine B Degradation",
    "DNA Plasmid Damage",
    "NIH/3T3 Cells",
    "Cell Death",
    "Combined Exposures"
  ],
  "keywords": [
    "microwave",
    "radio waves",
    "electronic smog",
    "sunscreen",
    "physical filters",
    "photocatalyst",
    "TiO2",
    "ZnO",
    "silica-coated",
    "NIH/3T3",
    "rhodamine B",
    "DNA plasmid"
  ],
  "suggested_hubs": [],
  "social": {
    "tweet": "In vitro study: ZnO/TiO2 sunscreen physical filters showed enhanced photocatalytic activity under combined UV + microwave exposure vs UV alone, with rhodamine B degradation, DNA plasmid damage, and reported NIH/3T3 cell death/uptake. (Photochem Photobiol Sci, 2022)",
    "facebook": "A 2022 in vitro paper reports that ZnO/TiO2 sunscreen physical filters had increased photocatalytic activity when exposed to UV plus microwave radiation compared with UV alone, alongside rhodamine B degradation, DNA plasmid damage, and NIH/3T3 cell uptake/cell death findings.",
    "linkedin": "Photochem Photobiol Sci (2022) reports an in vitro assessment of ZnO/TiO2 sunscreen physical filters under UV, microwave, and combined UV+microwave irradiation, finding enhanced photocatalytic activity with dye degradation, DNA plasmid damage, and NIH/3T3 cell uptake/cell death under combined exposure."
  }
}

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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: 10.1007/s43630-022-00259-3
PubMed: Not supplied

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