The scientific mission of AFRL’s Radio Frequency Radiation Branch is to understand the biophysical interactions between directed energy (DC-THz) and biological materials. Advanced knowledge of basic biophysical mechanisms related to directed energy exposures ensures the safety of our military personnel on the battlefield. To support this mission, our research group is exploring the interaction of high power short pulsed electromagnetic fields with humans. Exposure of mammalian cells to nanosecond duration electrical pulses (nsEP), a laboratory surrogate for free-field RF and MMW pulse exposure, has been shown to depolarize the cell plasma membranes causing irregular ion flow for minutes without evidence of lasting cell damage. Recent work has shown that high dose exposures can lead to irreversible plasma membrane damage in several cell types. Using genetic and proteomic techniques, we have identified molecular repair mechanisms which are specific to electrically delivered membrane stress.

Our laboratory is currently pursuing multiple research avenues to explore how pulsed electromagnetic fields interact with mammalian cells. First, we are utilizing our electrophysiological and optical microscope systems to record changes in membrane conductance in real time allowing for the determination of death thresholds. In addition, to investigate the impact that electrical pulses have on the conduction of action potentials, we are assessing the effect that nsEPs has on neurological cells. Second, we are looking at the cytotoxicity of nsEP on various cells types as a biological endpoint of exposure. We have found that nsEPs can be lethal to cells and that different cell types have varying levels of sensitivity to nsEP exposures. Lastly, we are developing theoretical models to describe and predict the impact and response of cells exposed to nsEP. Specifically, we are using analytical and numerical solutions using finite difference time domain and finite element algorithms to describe the impact of the nsEP on the cellular membrane. Our goal is to generate models that compliment empirical results enabling the prediction of cellular effect and lethality. The overarching aim of this modeling approach is to generate a comprehensive full human model that can predict the field distribution and biological impact of pulse exposures.

AFRL is interested in exploring the utility and safety of high power ultrashort electromagnetic pulses for use against both material and nonmaterial targets. Our nsEP laboratory directly supports this effort by supplying basic knowledge of how such pulses interact with biological systems. The nsEP team has extensive expertise in several research areas, including physics, optics, biomedical engineering, tissue engineering, biophysics, molecular biology, computer science, genomics, proteomics, bioinformatics, and systems biology. Our team’s unique set of expertise give us the ability to conduct high impact research that cuts across many different research disciplines. In addition, our team also works closely with university and industry partners.

 

Reference

Ibey BL, et al: Bioelectromagnetics 30: 92, 2009

 

key words

Electroporation; Nanosecond pulse; Membrane; Patch clamp; Atomic force microscopy; Fluorescent microscopy; Nanopores; Cell; Flow cytometry;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral and Senior applicants