Fluorescence depolarization studies of the phase transition in multilamellar phospholipid vesicles exposed to 1.0-GHz microwave radiation.
← Research streamNo shift of the phase transition was found during continuous-wave 1.0-GHz microwave exposure at specific absorption rates between 1 and 30 W/kg. No statistically significant differences were observed between exposed and control samples when temperature was ma…
Study snapshot
Abstract
The phase transition in multilamellar dimyristoylphosphatidylcholine (DMPC) vesicles was studied during exposure to continuous wave 1.0-GHz microwave radiation. Fluorescence depolarization measurements using a lipid-seeking molecular probe, diphenylhexatriene (DPH), were performed as a function of temperature. Semilog plots of microviscosity versus temperature illustrate the phase transition which shows a 5 degree C shift when the vesicles are treated with chloroform as a positive control. No shift of the phase transition was found during exposure to microwave radiation at specific absorption rates between 1 and 30 W/kg. Samples were exposed in a rectangular transmission line (TEM cell), and specific absorption rates were calculated from electrical measurements of incident, reflected, and transmitted power. Samples were exposed to increasing intensities of radiation, while the temperature was maintained at either 23.5 or 25.5 degree C; these temperatures represented the two ends of the phase transition region for these vesicles. No statistically significant difference was found between exposed and control samples. These results are in contrast to those of others using laser Raman spectroscopy to measure the phase transition in similar multilamellar vesicles exposed to microwave radiation.
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.
Main findings
No shift of the phase transition was found during continuous-wave 1.0-GHz microwave exposure at specific absorption rates between 1 and 30 W/kg. No statistically significant differences were observed between exposed and control samples when temperature was maintained at 23.5°C or 25.5°C.
Outcomes measured
- Phase transition temperature/shift in multilamellar DMPC vesicles
- Microviscosity vs temperature (fluorescence depolarization using diphenylhexatriene, DPH)
- Differences between exposed and control samples (statistical significance)
Limitations
- Sample size not reported in the abstract.
- Exposure duration not reported in the abstract.
- Only two maintained temperatures (23.5°C and 25.5°C) within the transition region were tested during increasing intensities.
- Findings noted as contrasting with other studies using a different measurement method (laser Raman spectroscopy), but details of those studies are not provided.
View raw extracted JSON
{
"study_type": "in_vitro",
"exposure": {
"band": "RF",
"source": null,
"frequency_mhz": 1000,
"sar_wkg": null,
"duration": null
},
"population": "Multilamellar dimyristoylphosphatidylcholine (DMPC) vesicles (with DPH fluorescence probe)",
"sample_size": null,
"outcomes": [
"Phase transition temperature/shift in multilamellar DMPC vesicles",
"Microviscosity vs temperature (fluorescence depolarization using diphenylhexatriene, DPH)",
"Differences between exposed and control samples (statistical significance)"
],
"main_findings": "No shift of the phase transition was found during continuous-wave 1.0-GHz microwave exposure at specific absorption rates between 1 and 30 W/kg. No statistically significant differences were observed between exposed and control samples when temperature was maintained at 23.5°C or 25.5°C.",
"effect_direction": "no_effect",
"limitations": [
"Sample size not reported in the abstract.",
"Exposure duration not reported in the abstract.",
"Only two maintained temperatures (23.5°C and 25.5°C) within the transition region were tested during increasing intensities.",
"Findings noted as contrasting with other studies using a different measurement method (laser Raman spectroscopy), but details of those studies are not provided."
],
"evidence_strength": "low",
"confidence": 0.78,
"peer_reviewed_likely": "yes",
"keywords": [
"microwave radiation",
"1.0 GHz",
"RF exposure",
"specific absorption rate",
"SAR",
"DMPC",
"multilamellar vesicles",
"phospholipid phase transition",
"fluorescence depolarization",
"diphenylhexatriene",
"microviscosity",
"TEM cell"
],
"suggested_hubs": []
}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.2250030304
PubMed: 7126281
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