Developing a soft micropatterned substrate to enhance maturation of human induced pluripotent stem cell-derived cardiomyocytes
Bibliographic record
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC CMs) offer numerous advantages as a biological model, yet their inherent immaturity compared to adult cardiomyocytes poses significant limitations. This study addresses hiPSC CM immaturity by introducing a physiologically relevant micropatterned substrate for long-term culture and maturation. An innovative microfabrication methodology combining laser etching and casting creates a micropatterned polydimethylsiloxane (PDMS) substrate with varying stiffness, from 2 to 50 kPa, mimicking healthy and fibrotic cardiac tissue. Platinum electrodes were integrated into the cell culture chamber enable pacing of cells at various frequencies. Subsequently, cells were transferred to the incubator for time-course analysis, ensuring contamination-free conditions. Cell contractility, cytosolic Ca 2+ transient, sarcomere orientation, and nucleus aspect ratio were analyzed in a 2D hiPSC CM monolayer up to 90 days post-replating in relation to substrate micropattern dimensions. Culturing hiPSC CMs for three weeks on a micropatterned PDMS substrate (2.5–5 µm deep, 20 µm center-to-center spacing of grooves, 2–5 kPa stiffness) emerges as optimal for cardiomyocyte alignment, contractility, and cytosolic Ca 2+ transient. The study provides insights into substrate stiffness effects on hiPSC CM contractility and Ca 2+ transient at immature and mature states. Maximum contractility and fastest Ca 2+ transient kinetics occur in mature hiPSC CMs cultured for two to four weeks, with the optimum at three weeks, on a soft micropatterned PDMS substrate. MS proteomic analysis further revealed that hiPSC CMs cultured on soft micropatterned substrates exhibit advanced maturation, marked by significant upregulation of key structural, electrophysiological, and metabolic proteins. This new substrate offers a promising platform for disease modeling and therapeutic interventions. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC CMs) have been transformative to disease-in-a-dish modeling, drug discovery and testing, and autologous regeneration for human hearts and their role will continue to expand dramatically. However, one of the major limitations of hiPSC CMs is that without intervention, the cells are immature and represent those in the fetal heart. We developed protocols for the fabrication of the PDMS matrices that includes variations in its stiffness and micropatterning. Growing our hiPSC CMs on matrices of comparable stiffness to a healthy heart (5 kPa) and grooves of 20 μm, generate heart cells typical of the healthy adult human heart.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".