Citations

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 10 6 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.

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) is highly contagious and causes coronavirus disease 2019 (COVID-19). Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is the most accurate and reliable molecular assay to detect active SARS-CoV-2 infection. However, a rapid increase in test subjects has created a global bottleneck in testing capacity. Given that efficient nucleic acid extraction greatly affects reliable and accurate testing results, we compared three extraction platforms: MagNA Pure 96 DNA and Viral NA Small Volume kit on MagNA Pure 96 (Roche, Basel, Switzerland), careGENETM Viral/Pathogen HiFi Nucleic Acid Isolation kit (WELLS BIO Inc., Seoul, Korea) on KingFisher Flex (Thermo Fisher Scientific, Rocklin, CA, USA), and SGRespiTM Pure kit (Seegene Inc., Seoul, Korea) on Maelstrom 9600 (Taiwan Advanced Nanotech Inc., Taoyuan, Taiwan). RNA was extracted from 245 residual respiratory specimens from the different types of samples (i.e., NPS, sputum, and saliva) using three different kits. The 95% limits of detection of median tissue culture infectious dose per milliliter (TCID50/mL) for the MagNA Pure 96, KingFisher Flex, and Maelstrom 9600 were 0.37–3.15 × 101, 0.41–3.62 × 101, and 0.33–1.98 × 101, respectively. The KingFisher Flex platform exhibited 99.2% sensitivity and 100% specificity, whereas Maelstrom 9600 exhibited 98.3–100% sensitivity and 100% specificity. Bland–Altman analysis revealed a 95.2% concordance between MagNA Pure 96 and KingFisher Flex and 95.4% concordance between MagNA Pure 96 and Maelstrom 9600, indicating that all three platforms provided statistically reliable results. This suggests that two modifying platforms, KingFisher Flex and Maelstrom 9600, are accurate and scalable extraction platforms for large-scale SARS-CoV-2 clinical detection and could help the management of COVID-19 patients.