An In Vitro Mat‐on‐Gel Construct for Engineering Cardiac Tissue

Abstract Topographical and mechanical features are two key factors for cell development. Here, an easy‐to‐make Mat‐on‐Gel construct is introduced to study the co‐effects of nanogeometry and stiffness on cardiomyocyte (CM) functional development in vitro. The construct consists of electrospun fibers and polydimethylsiloxane (PDMS) gel, providing both nanofibrillar structure and adjustable stiffness. Comparison studies of three different stiffness ranging from 19 to 52 kPa are conducted using a CM cell line: HL‐1 cells. Physical characterization shows that Mat‐on‐Gel constructs possess improved hydrophilicity than PDMS gel and reduced Young's modulus than electrospun mat. It results in better cell adhesion and enhanced cell metabolic activities. CMs on the Mat‐on‐Gel constructs also present more synchronous electrophysiological activities than those cultured on electrospun fibers or PDMS gel alone. In particular, lower gel stiffness results in more rapid calcium waves. This study collectively demonstrates the feasibility of this Mat‐on‐Gel construct and its potential usage as an in vitro platform for pharmaceutical studies.