Stretchable Low‐Impedance Nanocomposite Comprised of Ag–Au Core–Shell Nanowires and Pt Black for Epicardial Recording and Stimulation

Abstract

Cardiac resynchronization therapy (CRT) presents effective means to modulate cardiac conduction and related functions in heart failure patients. However, the conventional CRT delivers electric current at only two points on the heart, therefore, it is unable to provide comprehensive electrical support to the heart. Additionally, the CRT‐device structure faces several issues, such as those associated with the endocardial screw tip, which may cause myocardial degeneration, and the metal lead wire, which may lead to intravascular thrombosis and lead infection. Moreover, the conventional CRT has limitations in mechanically improving the cardiac contractility, which often cannot prevent further ventricular dilation. Here, a fabrication of an elastoconductive epicardial mesh using a stretchable low‐impedance nanocomposite comprising Ag–Au core–shell nanowires and platinum black (Pt black) in elastomer to provide a potential solution to the above‐mentioned clinical issues is reported. The proposed nanocomposite structure exhibits high stretchability, conductivity, and biocompatibility in combination with low impedance. These features facilitate the realization of high signal‐to‐noise ratios in electrocardiogram recordings, and high‐quality electrical stimulations. The proposed epicardial mesh is implanted on the surface of an animal heart with minimum traumatic stress, and is consequently able to conduct high‐quality cardiac recording and electrical stimulation in rodents.

Recent Advances in 1D Nanomaterial‐Based Bioelectronics for Healthcare Applications

“…Therefore, the Au‐coated Ag nanocomposite epicardial mesh could be used as a biocompatible implantable device for monitoring intracardiac electrogram and providing electrical stimulation. Sunwoo et al improved the electrical impedance to enhance the quality of the ECG signal and the feedback signal of electrical stimulation [ 121 ] ( Figure 6 a). Pt black, which is a 0D material, was added to a nanocomposite of Au‐coated Ag nanowires (140 nm mean diameter, 35 nm shell thickness, and 100 μm length) with SBS.…”

“…Reproduced with permission. [ 121 ] Copyright 2020, Wiley‐VCH GmbH. b) Biocompatible and ultrasensitive piezoelectric effective PVDF/Dopamine OPN and pressure sensor applications.…”

“…Furthermore, by implanting (wrapping) the OPN‐based sensor on the femoral artery of mice, several physiological states with slightly changing arterial pressure, including anesthesia, overdose anesthesia, Articulo mortis, and postmortem could be monitored. Some of the mentioned works [ 121,122 ] did not consider biocompatibility in their researches.…”

Material Design and Fabrication Strategies for Stretchable Metallic Nanocomposites

“…The Au shell significantly enhanced the material and biocompatibility of the device by protecting the Ag core from oxidation, which makes the nanocomposite more compatible with wearable and implantable device applications. [122] Furthermore, the phase-separated microstructure of the nanocomposite created by room temperature drying has improved the stretchability, as well as the conductivity. This performance improvement enables the electrocardiogram recording with a higher signal-to-noise ratio under the dynamic movement of the heart and provides better mechanical support for the contraction of the heart (Figure 9i).…”

Intrinsically stretchable electronics with ultrahigh deformability to monitor dynamically moving organs

“…An alternative approach makes use of all compliant material components to construct intrinsically stretchable electronic devices ( 13 , 17 , 25 ), which naturally exhibit skin-like mechanical properties without complicated structural designs. The recent studies have shown the substantial suppression of adverse reactions in these systems because of the improved mechanical compatibility with soft tissues during long-term implantable applications ( 21 , 26 , 27 ).…”