RF Safe

A Systematic Method to Explore Radio-Frequency Non-Thermal Effect on the Growth of Saccharomyces Cerevisiae

2022 · Mixed · Low evidence

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MixedLow evidencePaper 808

Yeast cells were exposed at 1.0, 3.162, 10, and 905 MHz and compared with two controls (one temperature-matched; one held 1°C higher). RF at 3.162 MHz reduced growth rate by 15.1%, RF at 1.0 MHz increased growth by 13.7%, the 4.3% increase at 10 MHz was repor…

Study snapshot

Publicationmanual · 2022
Study typein_vitro
Reported directionMixed
Evidence ratingLow

Abstract

A Systematic Method to Explore Radio-Frequency Non-Thermal Effect on the Growth of Saccharomyces Cerevisiae D. Ye, G. Cutter, T. P. Caldwell, S. W. Harcum, P. Wang. A Systematic Method to Explore Radio-Frequency Non- Thermal Effect on the Growth of Saccharomyces Cerevisiae.IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology. 6(1):52-60. March 2022, doi: 10.1109/JERM.2021.3101408. Abstract Radio frequency (RF) non-thermal (NT) bio-effects have been a subject of debate and attracted significant interests due to potential health risks or beneficial applications. In this work, we report a systematic method for broadband investigation of RF NT effects on Saccharomyces cerevisiae yeast growth. The method includes a transverse electro-magnetic (TEM) device and a dielectric spectroscopy technique for RF frequency selection. A stripline-based TEM device has two 240-μL chambers 3D printed for cell cultures. The fabricated device operates up to a few GHz and produces uniform RF fields for cell exposure testing. A vector network analyzer (VNA) was used to provide ~20 dBm continuous-wave (CW) RF power. The heating effects on cell growth were estimated to be negligible. Frequency regions, where large permittivity differences between the medium and yeast cultures were obtained and used to select RF testing frequencies, e.g., 1.0 MHz, 3.162 MHz, 10 MHz. These differences may indicate RF field gradients near cell membrane, and the gradients may affect local nutrient transport. Additionally, RF at 905 MHz is tested for comparison purpose. Yeast cells in the exponential growth phase were examined at four RF frequencies and compared with two controls. One control device held at the same temperature as the test device, while the other control was held at a temperature 1 degree C higher. The results showed that the RF fields at 3.162 MHz reduced yeast growth rates by 15.1%; however, the RF fields at 1.0 MHz enhanced cell growth by 13.7%, while the observed 4.3% growth rate increase at 10 MHz is insignificant and the RF fields at 905 MHz had no effects on the cell growth. These results showed a clear RF NT effects on S. cerevisiae growth that was frequency dependent. The hypothesized mechanisms of these effects, i.e., non- uniform RF fields near cell membranes and fluidic diodes in cell membrane ion channels may play important roles in nutrient transport, need to be further investigated. ieeexplore.ieee.org

Machine Enhanced Logic

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 directionmixed
PopulationSaccharomyces cerevisiae (yeast) cell cultures
Sample sizeNot supplied
ExposureRF
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Yeast cells were exposed at 1.0, 3.162, 10, and 905 MHz and compared with two controls (one temperature-matched; one held 1°C higher). RF at 3.162 MHz reduced growth rate by 15.1%, RF at 1.0 MHz increased growth by 13.7%, the 4.3% increase at 10 MHz was reported as insignificant, and 905 MHz had no effect; heating effects were estimated to be negligible.

Outcomes measured

  • Yeast growth rate (exponential growth phase)
  • Permittivity differences between medium and yeast cultures (dielectric spectroscopy for frequency selection)

Limitations

  • Exposure duration not stated in abstract
  • Sample size and replication not stated in abstract
  • Exposure metric (e.g., SAR, field strength) not reported in abstract (only ~20 dBm CW input power)
  • Findings are for yeast in vitro; generalizability to humans/animals not addressed in abstract
View raw extracted JSON
{
  "study_type": "in_vitro",
  "exposure": {
    "band": "RF",
    "source": "laboratory TEM/stripline exposure device with VNA continuous-wave power",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Saccharomyces cerevisiae (yeast) cell cultures",
  "sample_size": null,
  "outcomes": [
    "Yeast growth rate (exponential growth phase)",
    "Permittivity differences between medium and yeast cultures (dielectric spectroscopy for frequency selection)"
  ],
  "main_findings": "Yeast cells were exposed at 1.0, 3.162, 10, and 905 MHz and compared with two controls (one temperature-matched; one held 1°C higher). RF at 3.162 MHz reduced growth rate by 15.1%, RF at 1.0 MHz increased growth by 13.7%, the 4.3% increase at 10 MHz was reported as insignificant, and 905 MHz had no effect; heating effects were estimated to be negligible.",
  "effect_direction": "mixed",
  "limitations": [
    "Exposure duration not stated in abstract",
    "Sample size and replication not stated in abstract",
    "Exposure metric (e.g., SAR, field strength) not reported in abstract (only ~20 dBm CW input power)",
    "Findings are for yeast in vitro; generalizability to humans/animals not addressed in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radio frequency",
    "non-thermal effects",
    "Saccharomyces cerevisiae",
    "yeast growth",
    "TEM device",
    "stripline",
    "dielectric spectroscopy",
    "vector network analyzer",
    "continuous-wave",
    "frequency-dependent effects",
    "1.0 MHz",
    "3.162 MHz",
    "10 MHz",
    "905 MHz"
  ],
  "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: 10.1109/jerm.2021.3101408
PubMed: Not supplied

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