We present a battery-free radio frequency (RF) microwave activated wireless stimulator, 25 × 42 × 1.6 mm³ on a flexible substrate, featuring high current delivery, up to 60 mA, to stimulate engineered cardiac tissues. An external antenna shines 2.4 GHz microwave, which is modulated by an inverted pulse to directly control the stimulating waveform, to the wireless passive stimulator. The stimulator is equipped with an on-board antenna, multistage diode multipliers, and a control transistor. Rat cardiomyocytes, seeded on electrically conductive gelatin-based hydrogels, demonstrate synchronous contractions and Ca²⁺ transients immediately upon stimulation. Notably, the stimulator output voltage and current profiles match the tissue contraction frequency within 0.5–2 Hz. Overall, our results indicate the promising potential of the proposed wireless passive stimulator for cardiac stimulation and therapy by induction of precisely controlled and synchronous contractions.

中文翻译：

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工程心脏组织的无线被动刺激

我们提出了一种无电池射频（RF）微波激活无线刺激器，其在柔性基板上的尺寸为25×42×1.6 mm ³，具有高达60 mA的高电流传输能力，可刺激工程心脏组织。外部天线向无线无源刺激器发射2.4 GHz微波，该微波由反向脉冲调制以直接控制刺激波形。该刺激器配备了一个车载天线，多级二极管乘法器和一个控制晶体管。植入基于明胶的水凝胶上的大鼠心肌细胞显示出同步收缩和Ca ²⁺刺激后立即发生瞬变。值得注意的是，刺激器的输出电压和电流曲线在0.5–2 Hz内与组织收缩频率相匹配。总的来说，我们的结果表明，通过诱导精确控制和同步收缩，拟议的无线被动刺激器在心脏刺激和治疗方面具有广阔的发展前景。