Versatile electrical stimulator for cardiac tissue engineering—Investigation of charge-balanced monophasic and biphasic electrical stimulations

Abstract

The application of biomimetic physical stimuli replicating the in vivo dynamic microenvironment is crucial for the in vitro development of functional cardiac tissues. In particular, pulsed electrical stimulation (ES) has been shown to improve the functional properties of in vitro cultured cardiomyocytes. However, commercially available electrical stimulators are expensive and cumbersome devices while customized solutions often allow limited parameter tunability, constraining the investigation of different ES protocols. The goal of this study was to develop a versatile compact electrical stimulator (ELETTRA) for biomimetic cardiac tissue engineering approaches, designed for delivering controlled parallelizable ES at a competitive cost. ELETTRA is based on an open-source micro-controller running custom software and is combinable with different cell/tissue culture set-ups, allowing simultaneously testing different ES patterns on multiple samples. In particular, customized culture chambers were appositely designed and manufactured for investigating the influence of monophasic and biphasic pulsed ES on cardiac cell monolayers. Finite element analysis was performed for characterizing the spatial distributions of the electrical field and the current density within the culture chamber. Performance tests confirmed the accuracy, compliance, and reliability of the ES parameters delivered by ELETTRA. Biological tests were performed on neonatal rat cardiac cells, electrically stimulated for 4 days, by comparing, for the first time, the monophasic waveform (electric field = 5 V/cm) to biphasic waveforms by matching either the absolute value of the electric field variation (biphasic ES at ±2.5 V/cm) or the total delivered charge (biphasic ES at ±5 V/cm). Findings suggested that monophasic ES at 5 V/cm and, particularly, charge-balanced biphasic ES at ±5 V/cm were effective in enhancing electrical functionality of stimulated cardiac cells and in promoting synchronous contraction.

Short-term Electrical Stimulation Impacts Cardiac Cell Structure and Function

“…There are, however, limitations to the device presented. It is likely that the voltage density is not consistent throughout the well, meaning that the cells receive varied intensity of stimulation based on location (Gabetti et al, 2023). This is likely one reason why increased fibroblast rearrangement was observed closer to the electrodes compared to the center of the well (Figure 4c).…”

“…Other groups have employed various methods to induce maturity of fetal-like iPSC-derived CMs, including electrical (Gabetti et al, 2023; Ye & Black, 2014), mechanical (Karbassi & Murry, 2022; Morin et al, 2014; Ye & Black, 2014), and chemical stimuli (Abecasis et al, 2019; Yang et al, 2019). Electrical stimulation is popular due to the role of electrical signals in the cardiac system.…”

Engineering the cardiac tissue microenvironment

“…Advances in understanding of basic physiology in both healthy and diseased cardiac tissues in vivo, the development of more sophisticated techniques for designing and implementing biomimetic devices, and the implementation of powerful analytical tools have been essential in the development of more accurate and relevant cardiac models [9,10,87,159,278,289,290]. The implementation of these more biomimetic models further allows for more repeatable and powerful study of both typical cardiophysiology and response to CVD.…”

Accelerated osteogenesis of bone graft by optimizing the bone microenvironment formed by electrical signals dependent on driving micro vibration stimulation

“…Extensive research has confirmed that electrical signal waves (sine waves, triangle waves, square waves), as direct or indirect physical and physiological stimulation parameters, have independent and important regulatory effects on the biological behavior of cells and tissues. Gabetti et al [ 26 ] reported that electrical stimulation of different waveform pulses can significantly affect the synchronous contractile function of rat cardiac cells. Some studies found that biphasic square wave can make skin produce a higher sensory level than biphasic sine wave when studying the effect of different electrical waveform stimulation on skin sensory level [ [27] , [28] , [29] ].…”