Abstract 13447: An Injectable Conductive Polymer Hydrogel Improves Electrical Conduction Velocity in the Injured Heart
Bibliographic record
Abstract
Introduction: Scar formation after a myocardial infarction (MI) delays electrical impulse propagation, inducing dysynchronous cardiac activation and uncoordinated contraction. We generated an injectable biocompatible conductive polymer that not only stabilized the infarct region, but also facilitated electrical signal propagation across the scar tissue to enhance synchronous ventricular contraction. Methods/Results: Oxidative polymerization was employed to conjugate polypyrrole (PPY) to chitosan (CHI) and hydrogels were created by glutaraldehyde crosslinking. Biomaterials with 4 different PPY:CHI ratios (CHI, 3PPY:10CHI, 3 PPY:100 CHI, 3 PPY:1000CHI ) were generated. Electrical conductivity was measured by two-probe cyclic voltammetry. The 3PPY:10CHI ratio had significantly greater conductivity than the other concentrations (2.37х10-4±6.25х10-5S/cm, n=6, P<0.05). Improved electrical propagation was demonstrated when neonatal rat cardiomyocytes cultured on 3PPY:10CHI had significantly higher Ca2+ transient propagation velocity (by optical mapping with a fluo-4/AM indicator) than those cultured on other concentrations (17.25±2.23cm/s, n=15, P<0.05). Thus, 3PPY:10CHI was employed for in vivo studies employing a cryoinjury model (with a uniform scar size). Saline, CHI, and 3PPY:10CHI were injected into Sprague-Dawley rat hearts 1 week after injury. The sequence of cardiac electrical activation was visualized using an optical mapping system 1 month post-injection. Saline (57.7±2.5cm/s, n=4)- and CHI (47.1±3.5cm/s, n=3)-injected hearts showed disrupted propagation patterns and significantly reduced conduction velocity, while 3PPY:10CHI (74.3±4.7cm/s, n=5)-treated hearts had higher conduction velocities that were similar to healthy controls (81.3±0.59cm/s, n=3). Conclusion: A polypyrrole-conjugated chitosan hydrogel supported cell attachment and improved electrical conductivity in vitro. The 3PPY:10CHI biomaterial enhanced Ca2+ transient propagation in cultured cardiomyocytes and intra-myocardial injection of the material improved longitudinal electrical impulse propagation across the scar. This new biomaterial may be a new potential therapy to synchronize cardiac contraction.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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) | 0.003 | 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 source (direct Gemma or distilled Codex), 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".