Ink-jet printed stretchable sensors for cell monitoring under mechanical stimuli: A feasibility study

Impedance-based sensors represent a promising tool for cell monitoring to improve current invasive biological assays. A novel research field is represented by measurements performed in dynamic conditions, monitoring cells (e.g., myocytes) for which the mechanical stimulus plays an important role for promoting maturation. In this picture, we applied printed and stretchable electronics principles, developing a system able to evaluate cells adhesion during substrate cyclic strain. Cytocompatible and stretchable sensors were ink-jet printed using carbon-based ink on crosslinked poly(ϵ-caprolactone) electrospun mats. Moreover, a customized stretching device was produced, with a complete user interface to control testing condition, validated in order to correlate impedance changes with myoblasts - i.e., myocytes precursors - adhesion. Overall system sensitivity was evaluated using three different cell concentrations and DAPI imaging assay was performed to confirm myoblast adhesion. Preliminary results showed the possibility to correlate an average increase of impedance magnitude of 1kω every 15,000 cells/cm2 seeded, suggesting the possibility to discriminate between different cell concentrations, with a sensitivity of 80mω/(cells/cm2). In conclusion, the present system might be generalized in the development of future applications, including the differentiation process of cardiac myocytes with the aid of mechanical stimuli.