Effect of microwave radiation on the biophysical properties of liposomes.

Bioelectromagnetics · 2005 · Harm · Low evidence

← Research stream

HarmLow evidencePaper 6430

Study snapshot

PublicationBioelectromagnetics · 2005

Study typein_vitro

Reported directionHarm

Evidence ratingLow

Abstract

Steadily growing use of electromagnetic fields, especially in conjunction with wireless communication systems, has led to increasing public concern about possible health effects of electromagnetic radiation. However, besides the well-known thermal effect of electromagnetic fields on biological tissue, there is no clear evidence of further athermal interaction mechanisms with biological systems. The present study was designed to determine the changes in bilayer permeability in egg lecithin multilamellar vesicles after exposure to 900 MHz microwave radiation for a period of 5 h. Specific absorption rate (SAR) of the radiation for the investigated liposome sample was found to be 12 +/- 1 W/kg. Liposomal changes in permeability were monitored using a light scattering technique. Optical anisotropy of the liposome sample decreased dramatically upon exposure to microwave radiation, indicating structural changes in acyl chain packing. IR and NMR ((1)H NMR) studies, which have been employed to reveal structural alterations in microwave, exposed vesicles showed an increased damage upon exposure to microwave. The changes observed in the (1)H NMR spectrum of the microwave exposed sample indicated hydrolysis of carboxylic and phosphoric esters. IR study showed conformational changes in the acyl chains of the lipids upon microwave exposure. However, both IR and (31)P NMR did not show any appreciable changes in the head group part of the lipids.

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 directionharm

PopulationNot supplied

Sample sizeNot supplied

ExposureRF · 900 MHz · 12 W/kg · 5 h

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Egg lecithin multilamellar vesicles exposed to 900 MHz microwave radiation (SAR 12 ± 1 W/kg) for 5 h showed a dramatic decrease in optical anisotropy, interpreted as structural changes in acyl chain packing. IR and 1H NMR measurements indicated increased damage after exposure, including spectral changes consistent with hydrolysis of carboxylic and phosphoric esters and conformational changes in acyl chains, while IR and 31P NMR did not show appreciable changes in lipid head groups.

Outcomes measured

bilayer permeability
optical anisotropy (light scattering)
acyl chain packing/structural changes
IR spectroscopy changes
1H NMR changes (hydrolysis of esters)
31P NMR changes (head group)

Limitations

In vitro liposome model; findings may not translate to intact biological tissues or health outcomes
No sample size reported in abstract
Thermal vs athermal contribution not resolved in abstract (SAR is high and heating is not described)
Exposure conditions limited to a single frequency (900 MHz) and duration (5 h)

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "RF",
    "source": null,
    "frequency_mhz": 900,
    "sar_wkg": 12,
    "duration": "5 h"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "bilayer permeability",
    "optical anisotropy (light scattering)",
    "acyl chain packing/structural changes",
    "IR spectroscopy changes",
    "1H NMR changes (hydrolysis of esters)",
    "31P NMR changes (head group)"
  ],
  "main_findings": "Egg lecithin multilamellar vesicles exposed to 900 MHz microwave radiation (SAR 12 ± 1 W/kg) for 5 h showed a dramatic decrease in optical anisotropy, interpreted as structural changes in acyl chain packing. IR and 1H NMR measurements indicated increased damage after exposure, including spectral changes consistent with hydrolysis of carboxylic and phosphoric esters and conformational changes in acyl chains, while IR and 31P NMR did not show appreciable changes in lipid head groups.",
  "effect_direction": "harm",
  "limitations": [
    "In vitro liposome model; findings may not translate to intact biological tissues or health outcomes",
    "No sample size reported in abstract",
    "Thermal vs athermal contribution not resolved in abstract (SAR is high and heating is not described)",
    "Exposure conditions limited to a single frequency (900 MHz) and duration (5 h)"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave radiation",
    "900 MHz",
    "RF",
    "liposomes",
    "egg lecithin",
    "multilamellar vesicles",
    "SAR",
    "permeability",
    "light scattering",
    "optical anisotropy",
    "IR spectroscopy",
    "NMR",
    "1H NMR",
    "31P NMR",
    "acyl chain packing",
    "hydrolysis"
  ],
  "suggested_hubs": []
}

AI can be wrong. Always verify against the paper.

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: 10.1002/bem.20064
PubMed: 15768431

Read the original paper →

Related papers

← Back to the Research Library