Abstract Body (Do not enter title and authors here): Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) possess significant therapeutic potential for myocardial regeneration. However, clinical application remains constrained due to the immature phenotype of these cells, which impacts their engraftment as well as their electrical and mechanical integration post-transplantation into the injured heart. In particular, proper alignment of transplanted hiPSC-CMs is essential for synchronous contraction and efficient electromechanical coupling with native tissue. To address this critical clinical challenge, we engineered a tissue patch incorporating aligned electrospun nanofibers designed to enhance hiPSC-CM alignment and promote their structural maturation. Poly(caprolactone) (PCL) nanofibers were fabricated by electrospinning a 10% w/v solution in 1,1,1,3,3,3-hexafluoro-2-propanol at a flow rate of 0.5 mL/h. A voltage of 14 kV was applied to the spinneret and 3kV to the collector, positioned 13 cm away, with additional electrodes to induce fiber alignment. Scanning electron microscopy and ImageJ analysis confirmed fiber diameter and orientation. hiPSC-CMs (1 x 10⁶ cells) were seeded onto fiber scaffolds with varied diameters (1.0, 1.5, and 2.0 μm) and densities (low: 20%, moderate: 30%, high: 40%). Among these, 1.5 ± 0.2 μm diameter fibers with a density of 40 ± 3% provided the most effective topographical cues for promoting cell elongation and alignment. Immunofluorescence staining demonstrated that hiPSC-CMs cultured on aligned fibers exhibited enhanced cytoskeletal organization along the fiber axis. Morphological assessment over time showed progressive alignment by day 3. Importantly, hiPSC-CMs cultured on aligned fibers demonstrated stronger and more synchronized contractile activity compared to those cultured on flat glass surfaces. Together, these findings suggest that our aligned nanofiber-based cardiac patch promotes the structural and functional maturation of hiPSC-CMs, highlighting their potential as an advanced platform for improving cardiac cell therapy outcomes.