A 3D-printed Flexible Device for Measuring Concentric Contractile Force in In-Vitro Smooth Muscle Tissue Model

This paper presents a 3D-printed flexible device for quantifying the concentric contractile force of in vitro smooth muscle tissue. The device features circularly arranged flexible pillars that bend in response to tissue contraction. A calibration of linear displacement-force relationship was established through experiment and the computational simulation, showing only 3% deviation. As a demonstration, using this device, the passive concentric contractile force, the spontaneous force generated naturally as the muscle matures in culture over time, reached up to 44 μ$N$ per pillar on day 2 culturing smooth muscle tissue. Active contraction, controlled by potassium ion (K+), induced a 24% force increase, while dilation caused a 15% decrease relative to the steady state. This device enables precise evaluation of smooth muscle contractility for biomedical applications.