Silkuniene Giedre, Silkunas Mantas, Pakhomova Olga N, Semenov Iurii, Pakhomov Andrei G
Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
Bioelectrochemistry. 2025 Dec;166:109016. doi: 10.1016/j.bioelechem.2025.109016. Epub 2025 May 31.
Stimulation by pulsed electric fields (PEFs) normally follows PEF strength and weakens with distance from electrodes. Bipolar cancellation, caused by the electric field reversal, can offset this dependence. Remote focusing can be achieved by stimulation with nanosecond pulse packets that generate multiphasic, bipolar interference patterns near electrodes while preserving unipolar PEF at the remote target. We studied how the packet repetition rate, pulse width, and packet number influence remote focusing of electroporation and its suppression near electrodes. Cell monolayers were electroporated by packets of 300-, 600-, or 900-ns pulses from four needle electrodes arranged in a square with 15.3-mm diagonals. Electroporative dye uptake peaked at the center of the square and decreased laterally following Lorentzian distribution. Higher packet rates, longer pulses, and a smaller number of packets sharpened the central peak, reducing its full width at half maximum (FWHM) to 1.1 mm, which was 7.3 % of the diagonal and just 2.3 % of the electrode array area. At 0.2 MHz, electroporation near electrodes was 40-fold weaker than at the center, despite a 4-fold stronger electric field. This near-complete suppression of off-target effects, combined with sharper remote focusing, provides a critical advantage for precise targeting of PEF effects in biomedical applications.
脉冲电场（PEF）刺激通常随PEF强度变化，并随着与电极距离的增加而减弱。由电场反转引起的双极抵消可以抵消这种依赖性。通过用纳秒脉冲包进行刺激可以实现远程聚焦，该脉冲包在电极附近产生多相双极干涉图案，同时在远程目标处保持单极PEF。我们研究了包重复率、脉冲宽度和包数量如何影响电穿孔的远程聚焦及其在电极附近的抑制作用。细胞单层由来自四个针电极的300纳秒、600纳秒或900纳秒脉冲包进行电穿孔，四个针电极呈对角线为15.3毫米的正方形排列。电穿孔染料摄取在正方形中心达到峰值，并沿洛伦兹分布横向降低。更高的包速率、更长的脉冲和更少的包数量使中心峰值变锐，将其半高宽（FWHM）减小到1.1毫米，这是对角线的7.3%，仅为电极阵列面积的2.3%。在0.2MHz时，尽管电场强度高4倍，但电极附近的电穿孔比中心处弱40倍。这种对脱靶效应的近乎完全抑制，再加上更尖锐的远程聚焦，为生物医学应用中PEF效应的精确靶向提供了关键优势。
