Wireless Passive Stimulation of Engineered Cardiac Tissues

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Materials Science

Background:

• Engineered cardiac tissues require precise electrical stimulation for functional development.
• Existing cardiac stimulators often rely on invasive or wired approaches, limiting their application.
• Wireless, battery-free solutions are desirable for long-term implantation and reduced tissue damage.

Purpose of the Study:

• To develop and evaluate a novel battery-free, wireless stimulator for engineered cardiac tissues.
• To demonstrate the capability of the stimulator to induce synchronous contractions and calcium transients in cardiomyocytes.
• To assess the compatibility of the stimulator's output parameters with cardiac tissue response.

Main Methods:

• A flexible, passive radio frequency (RF) microwave-activated wireless stimulator (25 × 42 × 1.6 mm³) was designed and fabricated.
• The stimulator utilizes an on-board antenna, multistage diode multipliers, and a control transistor, powered by external 2.4 GHz microwave energy.
• Rat cardiomyocytes cultured on conductive hydrogels were stimulated wirelessly, and their contractions and Ca²+ transients were monitored.

Main Results:

• The wireless stimulator successfully delivered high current (up to 60 mA) to the engineered cardiac tissues.
• Synchronous contractions and Ca²+ transients were observed in rat cardiomyocytes immediately upon wireless stimulation.
• The stimulator's output voltage and current profiles effectively matched the tissue contraction frequency (0.5-2 Hz).

Conclusions:

• The developed battery-free wireless stimulator shows significant promise for cardiac stimulation applications.
• Precise control over cardiac tissue contractions can be achieved wirelessly, paving the way for new therapeutic strategies.
• This technology offers a potential solution for non-invasive, long-term cardiac pacing and regeneration therapies.