Nano-textured polyimide cantilever for enhancing the contractile behavior of cardiomyocytes and its application to cardiac toxicity screening

Polydimethylsiloxane (PDMS) cantilevers with hydrophobic nature have been extensively utilized in biosensors for their relatively good mechanical properties and biocompatibility. However, when nanostructures are formed on the surface of PDMS, it is difficult to observe the long-term behavior of cardiomyocytes because of the inherent hydrophobicity of the material. In this paper, we propose the use of nanotextured polyimide (PI) cantilevers to measure cardiac contractility. The proposed PI material not only has very high biocompatibility, but also has high thermal resistance which is useful for metal deposition and sterilization processes. Additionally, an oxygen-plasma-treated PI cantilever surface provides more suitable environment for cardiomyocytes that have a sarcomere length greater than 2.0 μm, which is close to the size of mature adult cardiomyocytes. Immunofluorescence experiments were conducted to analyze the biological characteristics of cardiomyocytes grown on the nanotextured PI cantilevers. Following these preliminary experiments, the fabricated PI cantilevers were utilized to measure the contractile behavior of drug-treated cardiomyocytes. The different contractile behaviors of cardiomyocytes grown on PDMS and PI cantilevers were also compared using a laser-based displacement sensor. We believe that the nanotextured PI cantilever has significant potential for basic studies on the contraction of matured cardiomyocytes and their interaction with drugs.