Abstract 16588: A Conductive Biomaterial Patch to Repair a Cardiac Defect
Introduction: Both stable and biodegradable biomaterials have been used to repair cardiac defects or stabilize the myocardial infarct after an MI. However, none of these biomaterials conducts electrical activity and all further increase asynchronous contraction. They may contribute to arrhythmias. This study evaluated the conductivity and efficiency of a newly synthesized conductive polypyrrole-chitosan (PPy-Chi) gelfoam patch in vitro for cardiomyocyte function and cardiac repair in vivo.
Methods: The PPy-Chi conductive biomaterial was injected into gelfoam (Gel) to form a 3-dimensional conductive PPy-Chi patch. The tensile strength was evaluated by stress-strain curves. Conductivity was measured with two-probe cyclic voltammetry and ECG voltammetry. In vitro, biocompatibility was investigated using cultured neonatal rat cardiomyocytes in the Gel, Chi, or PPy-Chi patches (n=8/group). In vivo, a full thickness right ventricular outflow tract defect was created in adult rats after cryoinjury and patches were stitched for repair. Four weeks after implantation, the cardiac electrical activation sequence and conduction velocity were evaluated using an optical mapping system. Patch conductivity was also measured ex vivo using a cardiac muscle stimulation method and recording the resultant ECG (n=6/group).
Results: The PPy-Chi patch had higher mean breaking stress compared to the other two patches (19.3±3.2 (Kpa) vs. 8.2±1.5 in Gel and 12.4±2.8 in Chi, p<0.01) and had the highest conductivity (p<0.01). In vitro, none of the patches altered cell growth. The Ca2+ transient velocity of the cardiomyocytes cultured on the PPy-Chi patch was 2.5 fold higher than those on the Gel and Chi patches (p<0.01). In the in vivo study, at 4 weeks post-implantation, optical mapping demonstrated that PPy-Chi patch-implanted hearts had faster conduction velocities measured on the epicardial surface 81.8±3.9 (cm/s) vs. 59.7±3.9 in Gel and 66.1±8.8 in Chi patches, p<0.01). Ex vivo patch conductivity testing also revealed that the PPy-Chi patch was twofold higher than the Chi patch (p<0.01).
Conclusions: This PPy-Chi patch was biocompatible and had better conductivity than the other patches tested. It may provide an additional benefit for cardiac repair.
Author Disclosures: S. He: None. H. Song: None. J. Wu: None. R.D. Weisel: None. R. Li: Research Grant; Significant; Heart and Stroke Foundation of Canada (G140005765).
- © 2016 by American Heart Association, Inc.