Dielectric Measurements and Modeling to Characterize Pulsed RF Bioeffects
Abstract
DIELECTRIC MEASUREMENTS AND MODELING TO CHARACTERIZE PULSED RF BIOEFFECTSProgram Officer: Tim Bentley, ONR Code 342Both wideband [electric pulses (EPs) from picosecond to millisecond duration] and narrowband (Hz to THz) electromagnetic radiation have widespread clinical and defense applications, including wound healing, microorganism inactivation, platelet activation, and nonlethal defense; however, characterizing their thermal and nonthermal biological effects from the molecular to the organism level remains challenging.Ongoing work has examined the impact of heating and membrane permeabilization for short-duration pulses and radiofrequency waves, as well as developing rapid calculations for membrane permeabilization. The proposed effort seeks to expand these efforts by experimentally measuring the response of cellular dielectric properties to changes in temperature and modeling vestibular phenomena under exposure to pulsed RF radiation in coordination with ongoing work at the Army Research Laboratory (ARL). The response of tissues and biological cells depends critically on the dielectric properties of these components, specifically their frequency-dependent permittivity and conductivity. While the sensitivity of these properties to temperature is well-known, detailed characterization of this behavior with temperature, particularly at the cellular level, has not been performed. This effort proposes to measure the changes in the conductivity and permittivity at the cellular level using a two-shell model consisting of the cell membrane, cytoplasm, nuclear envelope, and nucleoplasm. The temperature-dependent variation of these parameters will be incorporated into our team#s models of cellular response to RF radiation to assess the resulting changes in behavior. Tissue exposure to sub-microsecond electromagnetic (EM) pulsed energy gives rise to acoustic responses. As simple examples and likely targets of RF bioeffects, we will consider the auditory and vestibular organs. Both organ systems feature hair cells that are able to transduce acoustic stimuli from electrical signals based on mechano-sensitive channels present in the hair cells. It is very likely that local heating of the auditory canal may give rise to thermoelastic expansion and pressure changes. We will perform appropriate multi-physics simulations linking electromagnetic radiation from a source to the hair cells. The results from these studies will be examined in the context of waveforms of various parameters of interest to ARL and, as feasible, with ongoing ARL experiments. This work will provide an important extension to ongoing modeling work funded by the Office of Naval Research (ONR) and provide important conceptual understanding of in vitro work that is proposed under a separate proposal to the Army Research Office (ARO). This proposal requests $234,126.00 with a period of performance from 01JUN2023 to 30SEP2024. This abstract is publicly releasable.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 11, 2023
- Source ID
- N000142312774
Entities
People
- Allen L Garner
Organizations
- Office of Naval Research
- Purdue University
- United States Navy