Sun Zhengwu, Sen Payel, Hamers Jules, Seidel Thomas, Dendorfer Andreas, Kameritsch Petra
Walter-Brendel-Centre of Experimental Medicine, LMU Klinikum, Ludwig-Maximilians-University, 81377 München, Germany.
DZHK (German Center for Cardiovascular Research), Partner Site Munich, Munich Heart Alliance (MHA), 80336 Munich, Germany.
Bioengineering (Basel). 2025 Feb 26;12(3):234. doi: 10.3390/bioengineering12030234.
The cultivation of excitable cells typically profits from continuous electrical stimulation, but electrochemical consequences are mostly harmful and must be minimized. The properties of the electrode materials and stimulation impulses are key. Here, we developed an easy method to analyze the electrochemical impact of biphasic, current-controlled impulses, applied via graphite electrodes, using phenol red as the redox indicator. We also tested the stimulation conditions for the long-term cultivation of myocardial tissue. The colorimetric assay was able to detect ±0.2% deviations in typical positive and negative pulse charges. Phenol red was best preserved (20% degradation over 24 h) by impulses of equivalent positive and negative charges (full charge balance), generated with either manual calibration, capacitive electrode coupling, or feedback regulation of electrode polarization. Feedback regulation established full charge balance at pre-pulse voltages of about 300 mV, but also provided the option to selectively compensate irreversible electrode reactions. Modifications to shape and timing did not affect the electrochemical effects of symmetric impulses. Charge-balanced stimulation maintained more than 80% of the contractility of porcine left ventricular myocardium after 10 days of culture, whereas disbalances of 2-4% provoked weakening and discoloration of the tissues. Active polarization regulation, in contrast to capacitive electrode coupling, reproduced the biological advantages of full charge balance.
可兴奋细胞的培养通常受益于持续的电刺激，但电化学效应大多是有害的，必须将其降至最低。电极材料和刺激脉冲的特性是关键。在此，我们开发了一种简单的方法，以苯酚红作为氧化还原指示剂，分析通过石墨电极施加的双相电流控制脉冲的电化学影响。我们还测试了心肌组织长期培养的刺激条件。比色法能够检测典型正负脉冲电荷中±0.2%的偏差。通过手动校准、电容性电极耦合或电极极化的反馈调节产生的等量正负电荷脉冲（完全电荷平衡），能最好地保存苯酚红（24小时内降解20%）。反馈调节在约300 mV的预脉冲电压下建立了完全电荷平衡，但也提供了选择性补偿不可逆电极反应的选项。对形状和时间的修改并不影响对称脉冲的电化学效应。电荷平衡刺激在培养10天后维持了猪左心室心肌超过80%的收缩力，而2-4%的不平衡则导致组织减弱和变色。与电容性电极耦合相比，主动极化调节再现了完全电荷平衡的生物学优势。
