Enabling actuation and sensing in organs-on-chip using electroactive polymers

Organ-on-chip (OoC) devices are in rising demand for high-throughput and low-cost development and toxico-logical screening of chemicals and pharmaceuticals, as they accurately mimic in vitro physiological conditions as in the human body. In particular, OoCs are urgently needed for screening cardiovascular drug toxicity. Physiological relevance of cardiovascular cell cultures requires moving substrates. To date cell culture substrates have been commonly actuated by pneumatic systems, which are bulky, expensive and non-user-friendly, and may thus limit the adoption of OoCs by researchers and industry. In this paper we propose the first actuating and sensing smart material-based OoC device and demonstrate its functionality by culturing human vascular smooth muscle cells (vSMC). Our device utilizes a single ionic polymer metal composite (IPMC)-based transducer to provide both actuation and sensing. The soft IPMC substrate allows to intermittently apply cyclic loading to tissues and to sense their spontaneous contractions. We integrated the transducer within a compact, easy-to-operate, economically affordable and scalable OoC prototype, which achieves an actuation range of 0.2 mm and 0.72 V/mm sensing resolution. The 0.1 % strain induced by actuation on cells accurately corresponds to in vitro strains for vSMCs. We successfully grew vSMCs on the IPMC substrate, and actuated them for 150 min at 1 Hz. Fluorescent staining showed no evidence of adverse effects. These results are a major step towards versatile OoCs for a wide variety of biological modelling of human tissues.