Paintable and Rapidly Bondable Conductive Hydrogels as Therapeutic Cardiac Patches

Abstract

In recent years, cardiac patches have been developed for the treatment of myocardial infarction. However, the fixation approaches onto the tissue through suture or phototriggered reaction inevitably cause new tissue damage. Herein, a paintable hydrogel is constructed based on Fe -triggered simultaneous polymerization of covalently linked pyrrole and dopamine in the hyperbranched chains where the in situ formed conductive polypyrrole also uniquely serves to crosslink network. This conductive and adhesive hydrogel can be conveniently painted as a patch onto the heart surface without adverse liquid leakage. The functional patch whose conductivity is equivalent to that of normal myocardium is strongly bonded to the beating heart within 4 weeks, accordingly efficiently boosting the transmission of electrophysiological signals. Eventually, the reconstruction of cardiac function and revascularization of the infarct myocardium are remarkably improved. The translatable suture-free strategy reported in this work is promising to address the human clinical challenges in cardiac tissue engineering.

Electroconductive hydrogels for biomedical applications

“…Copyright 2019 The Royal Society of Chemistry) (b) Schematic illustration of the formation of a chemical crosslinking conductive and adhesive hydrogel. (Reprinted with permission from Liang et al (). Copyright 2018 Wiley) (c) Schematic illustrations of the 3D hierarchical microstructure of PANI hydrogel via supramolecular crosslinking.…”

“…Copyright 2017 Wiley) (b) Schematic illustration of the formation of a conductive and adhesive polypyrrole hydrogel, and its application as heart patches. (Reprinted with permission from Liang et al (). Copyright 2018 Wiley)…”

Conjugated Polymers in Bioelectronics: Addressing the Interface Challenge

“…Most recently CPs are finding their way into cardiac applications, where the hope is that conditions affecting the signal propagation across the heart can be mitigated or the conduction can be preserved post surgical repair of cardiac defects . Traditionally tissue engineering has focused on conventional insulating materials which can either deliver cells or provide mechanical support.…”

“…Additionally, the nature of electrical conduction in normal hearts occurs preferentially at the epicardial surface . A fast‐gelating, PPy based, hydrogel was developed that was painted onto the heart and rapidly bonded to the cardiac wall . Due to its electroactive nature, the conduction of the electrophysiological signals across the heart and ventricle wall thickness was improved, and the infarct size was decreased (Figure B).…”

“…While sutures are widely used for fixing implants to the host tissue, they can compromise the structural and electronic integrity of the bioelectronic device. Alternative techniques, such as paintable conductive and light activated adhesives, are technologies worth investigating in conjunction with the development of the device itself (Figure B,C). Other approaches include the development of self‐healing polymers which could spontaneously repair the damage caused by the suturing process …”