ID: 2184

• Title:
  Biological responses of excitable cells after burst of low energy nanosecond electric pulses
  
  Authors:
  

  Tolstykh G.P. (1), Maldonado L.A. (1), Gomez J.A. (1), Gamboa B.M. (2), Whitmore J.N. (2), Kasukonis B.M. (2).
  
  (1) General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
  (2) Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
  
  
  

  
  
  Abstract:
  High-energy nanosecond electric pulses (NSEPs) have been successfully utilized in clinical applications for tissue ablation and intracellular drug delivery. While higher electric field strengths favor these applications, damage-free electrical neurostimulation remains difficult. The known negative outcome of neuromuscular stimulation by NSEPs is an electroporation of the cellular plasma membrane. In contrast, low-energy NSEPs compressed into MHz trains are reported not to cause adverse biological effects. Thus, understanding stimulation versus damage thresholds after exposure to bursts of low-energy NSEPs is critical for developing novel damage-free neuromodulation devices. This study was designed to evaluate stimulation versus damage effects of 5 MHz bursts of low energy NSEPs and compare to a single us/ms electric pulse (EP) similar to NSEP trains duration and amplitude. A finite element analysis was conducted to define optimal stimulation electrode placement to reach a low electric field (0.01–0.2 kV/cm) around mouse C2C12 muscular cells and rat primary hippocampal neurons. The intracellular calcium responses and YoPro1 uptakes were evaluated using a high-speed imaging system after exposure to 5 MHz NSEP trains and matching single-long EPs. While the NSEP trains induced Ca2+ responses immediately after exposure and without noticeable morphological changes, the single EPs produced delayed responses with cellular damage detected by YoPro1 uptake. Despite lower energy impact induced by NSEP bursts, the amplitude of Ca2+ increases appear to be similar to amplitude after higher energy single us/ms EPs. However, the decay kinetic of elevated intracellular Ca2+ after NSEP bursts was much faster, displaying better baseline intracellular Ca2+ recovery. Thus, the MHz compressed trains of low-energy NSEPs demonstrate improved potential for safer neuromuscular stimulation than high-energy NSEPs or conventional us/ms EPs. The results of this work will lead to a better understanding of low-energy NSEPs neuromuscular stimulation and/or modulation mechanisms and open the door for the development of novel biomedical applications.
  
  Keywords:
  Low energy NSEP, MHz compression, us and ms EP, neuromuscular stimulation, Ca2+, YoPro1
  
  Refs:
  
  
  Topic 1:
  1. Biological responses (molecular, subcellular, cellular and intercellular)
  
  Topic 2:
  8. Cell and tissue stimulation, wound healing