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Effect of microwave radiation on the permeability of carbonic anhydrase loaded unilamellar liposomes.

Bioelectromagnetics · 1994 · Mixed · Low evidence

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MixedLow evidencePaper 6318

After 120 min of 2.45 GHz microwave exposure (6 mW/g), PNPA diffusion through the liposome lipid bilayer increased about twofold compared with temperature controls, with a time-dependent effect. Enzyme activity increased over 120 min (22.3% to 80%), and highe…

Study snapshot

PublicationBioelectromagnetics · 1994
Study typein_vitro
Reported directionMixed
Evidence ratingLow

Abstract

The influence of 2.45 GHz microwave exposure (6 mW/g) on the diffusion processes in enzyme-loaded unilamellar liposomes as bioreactors was studied. The enzyme carbonic anhydrase (CA) was entrapped into cationic unilamellar vesicles. Previous kinetic experiments showed a very low self-diffusion rate of the substrate p-nitrophenyl acetate (PNPA) across intact liposome bilayer. A twofold increase in the diffusion rate of PNPA through the lipid bilayer was observed after 120 min of microwave radiation compared to temperature control samples. The microwave effect was time dependent. The enzyme activity, as a function of increased diffusion of PNPA, rises over 120 min from 22.3% to 80%. The increase in stearylamine concentration reduces the enzyme activity from 80% to 65% at 120 min. No enzyme leakage was observed.

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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 directionmixed
PopulationNot supplied
Sample sizeNot supplied
Exposuremicrowave · 2450 MHz · 6 W/kg · 120 min
Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

After 120 min of 2.45 GHz microwave exposure (6 mW/g), PNPA diffusion through the liposome lipid bilayer increased about twofold compared with temperature controls, with a time-dependent effect. Enzyme activity increased over 120 min (22.3% to 80%), and higher stearylamine concentration reduced activity at 120 min (80% to 65%). No enzyme leakage was observed.

Outcomes measured

  • Diffusion rate of p-nitrophenyl acetate (PNPA) across liposome bilayer
  • Enzyme activity (carbonic anhydrase) as a function of substrate diffusion
  • Enzyme leakage from liposomes

Limitations

  • In vitro liposome system; findings may not generalize beyond this model
  • Sample size not reported in abstract
  • Only one frequency and exposure level described in abstract
  • Outcome is a biophysical/biochemical proxy (diffusion/enzyme activity) rather than health endpoints
View raw extracted JSON
{
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": 2450,
    "sar_wkg": 6,
    "duration": "120 min"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Diffusion rate of p-nitrophenyl acetate (PNPA) across liposome bilayer",
    "Enzyme activity (carbonic anhydrase) as a function of substrate diffusion",
    "Enzyme leakage from liposomes"
  ],
  "main_findings": "After 120 min of 2.45 GHz microwave exposure (6 mW/g), PNPA diffusion through the liposome lipid bilayer increased about twofold compared with temperature controls, with a time-dependent effect. Enzyme activity increased over 120 min (22.3% to 80%), and higher stearylamine concentration reduced activity at 120 min (80% to 65%). No enzyme leakage was observed.",
  "effect_direction": "mixed",
  "limitations": [
    "In vitro liposome system; findings may not generalize beyond this model",
    "Sample size not reported in abstract",
    "Only one frequency and exposure level described in abstract",
    "Outcome is a biophysical/biochemical proxy (diffusion/enzyme activity) rather than health endpoints"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "2.45 GHz",
    "microwave radiation",
    "SAR 6 mW/g",
    "liposomes",
    "unilamellar vesicles",
    "carbonic anhydrase",
    "membrane permeability",
    "diffusion",
    "p-nitrophenyl acetate",
    "stearylamine"
  ],
  "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: 10.1002/bem.2250150405
PubMed: 7980659

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