A Carbon-Based Biosensing Platform for Simultaneously Measuring the Contraction and Electrophysiology of iPSC-Cardiomyocyte Monolayers

Abstract

Heart beating is triggered by the generation and propagation of action potentials through the myocardium, resulting in the synchronous contraction of cardiomyocytes. This process highlights the importance of electrical and mechanical coordination in organ function. Investigating the pathogenesis of heart diseases and potential therapeutic actions in vitro requires biosensing technologies which allow for long-term and simultaneous measurement of the contractility and electrophysiology of cardiomyocytes. However, the adoption of current biosensing approaches for functional measurement of in vitro cardiac models is hampered by low sensitivity, difficulties in achieving multifunctional detection, and costly manufacturing processes. Leveraging carbon-based nanomaterials, we developed a biosensing platform that is capable of performing on-chip and simultaneous measurement of contractility and electrophysiology of human induced pluripotent stem-cell-derived cardiomyocyte (iPSC-CM) monolayers. This platform integrates with a flexible thin-film cantilever embedded with a carbon black (CB)-PDMS strain sensor for high-sensitivity contraction measurement and four pure carbon nanotube (CNT) electrodes for the detection of extracellular field potentials with low electrode impedance. Cardiac functional properties including contractile stress, beating rate, beating rhythm, and extracellular field potential were evaluated to quantify iPSC-CM responses to common cardiotropic agents. In addition, an in vitro model of drug-induced cardiac arrhythmia was established to further validate the platform for disease modeling and drug testing.

Biohybrid 3D Printing of a Tissue‐Sensor Platform for Wireless, Real‐Time, and Continuous Monitoring of Drug‐Induced Cardiotoxicity

“…In a recent study by Dou et al, a tissue‐sensor platform that can simultaneously monitor both electrical signals and contractility of 2D cardiac monolayers was developed. [ 24 ] They compared cardiac functional properties, such as contractile motion, beating rate, and extracellular field potential, before/after treating common cardiotropic medications. Furthermore, drug‐induced cardiac arrhythmia, which is one of the representative cardiotoxic effects, was able to be established.…”

“…Biofabrication technology has recently contributed to the creation of cardiac microphysiological systems (MPS) that are structurally and functionally similar to those of the human heart. [16][17][18] Numerous cardiac MPS are manufactured using soft lithography techniques that involve multiple processes, masks, and specialized equipment, [19][20][21][22][23][24][25][26] which complicates the implementation of multimaterial and 3D complex structures. Furthermore, these approaches are difficult to provide 3D structural cues to cardiac MPS because simple combinations of cells, biomaterials, and bioactive components are used.…”

Performance Deficiency Improvement of CNT-Based Strain Sensors by Magnetic-Induced Patterning

“…Particularly, resistive-type strain sensors have attracted considerable research interest owing to their simple structure and low cost. − Stretchable resistive strain sensors are typically composed of flexible substrates coupled with conductive sensing layers. In contrast to conventional sensor substrates such as metals and semiconductors, which tolerate limited sensitivity and stretchability (gauge factor (GF) of ∼2 and maximum strain of 5%), emerging flexible polymer substrates including polydimethylsiloxane (PDMS), silicon rubber, Ecoflex, and polyurethane (PU) are capable of exhibiting excellent stretchability. − The conductive sensitive layer in strain sensors is mainly composed of inorganic conductive materials, such as carbon nanotubes (CNTs), ,, silver nanowires (Ag-NWs), , graphene, , metallic nanoparticles, , and their hybrid micro/nanostructures. , …”

Ultrathin and Flexible Bioelectronic Arrays for Functional Measurement of iPSC-Cardiomyocytes under Cardiotropic Drug Administration and Controlled Microenvironments

“…Patients with either congenital or acquired heart diseases commonly have abnormal contraction symptoms, manifested as weak contraction force, heart fibrillation, and arrhythmic beating. To this end, developing biosensing technologies to quantify contractility changes of in vitro cardiac models is essential for analyzing cardiomyocyte contractile functions and testing the therapeutic efficacy or potential cardiotoxicity of drug candidates. , To date, several biosensing techniques/platforms have been developed for the measurement of cardiac contraction of a single cardiomyocyte, 2D monolayers, and 3D in vitro cardiac tissues. − For example, video-based analysis of cardiomyocyte beating displacement or strain magnitude under microscopy, , atomic force microscopy (AFM), impedance change of interdigitated electrodes induced by cardiomyocyte beating, traction force microscopy, cell drum, and optical tracking of cantilevers or tissue wire deflection have all been developed. , Piezoresistive strain sensors were also integrated into flexible structures to realize continuous electrical readout of cardiomyocyte contractility. , Challenges exist in how to increase device sensitivity to accurately capture weak contractility signals generated by in vitro cardiac models, how to increase platform capacity for high-throughput drug testing, and how to integrate stimulating components, while investigating microenvironmental cues on cardiomyocyte development and maturation, and maladaptive remodeling.…”

“…The spherical shape of zero-dimensional CB particles facilitated the formation of point contact between nanoparticles or particle clusters, which can be readily disrupted under low strain magnitude . To evaluate the piezoresistive strain sensing performance, a uniaxial tensile test (ε max = 0.3%) was conducted to mimic the low strain magnitude as generated by the contraction of cardiomyocyte monolayers . Relative resistance change ( ΔR / R 0 ) under cyclic tensile stretch was simultaneously recorded.…”