Automated fabrication of a scalable heart-on-a-chip device by 3D printing of thermoplastic elastomer nanocomposite and hot embossing

This study presents an automated, scalable workflow for fabricating next-generation multiwell heart-on-a-chip devices by combining hot embossing of polystyrene substrates with precision 3D printing of quantum-dot-doped thermoplastic elastomer (TPE/QD) microwires. Built-in carbon electrodes enable long-term electrical stimulation, while fluorescent microwires serve as integrated force sensors for engineered human iPSC-derived cardiac tissues. Compared to manual Biowire II fabrication, the automated method reduced per-well production time by more than four orders of magnitude and enabled seamless expansion to 24- and 96-well formats. Cardiac tissues matured under electrical pacing exhibited improved excitation thresholds, enhanced capture rates, positive force–frequency behavior, robust sarcomeric alignment, and physiologically relevant drug responses to nifedipine and lidocaine. This automated platform significantly advances high-throughput cardiac tissue engineering and preclinical pharmacological screening. :contentReference[oaicite:1]{index=1}