Hydrogel Strain Sensors for Integrating Into Dynamic Organ-on-a-Chip.

Current hydrogel strain sensors have never been integrated into dynamic organ-on-a-chip (OOC) due to the lack of sensitivity in aqueous cell culture systems. To enhance sensing performance, a novel strain sensor is presented in which the MXene layer is coated on the bottom surface of a pre-stretched anti-swelling hydrogel substrate of di-acrylated Pluronic F127 (F127-DA) and chitosan (CS) for isolation from the cell culture on the top surface. The fabricated strain sensors display high sensitivity (gauge factor of 290.96), a wide sensing range (0-100%), and high repeatability. To demonstrate its application, alveolar epithelial cells are cultivated on the top surface of the hydrogel strain sensor forming alveolar barriers, and then integrated into dynamic lung-on-a-chip (LOC) systems. This system can sensitively monitor normal physiological breathing, pathological inflammation stimulated by lipopolysaccharide (LPS), and alleviated inflammation through drug intervention.