A Novel Platform for In Vitro Cellular Stretching and Imaging

Cells respond to mechanical cues from their environment, such as changes in extracellular matrix (ECM) stiffness and cyclic strain, which regulate cellular processes including cell fate determination, intercellular communication, and development. Alterations in these forces contribute to or drive disease progression in conditions like asthma, hypertension, and cancer. While existing in-vitro stretching devices can impose uniaxial or isotropic strains, they often use non-physiological stiffnesses, limit live imaging, or cannot achieve high strain amplitudes relevant to physiological and pathological conditions. Here, we present a compact, microscope-compatible stretcher device that applies controlled isotropic or uniaxial strain to adherent cells on elastomeric culture dishes. These dishes feature a tunable Young's modulus and are compatible with a variety of matrix protein coatings for cell adhesion, allowing independent modulation of substrate stiffness and ECM composition. Importantly, the device's ease of operation is facilitated by its stepper motor-driven design, which supports the generation of programmable cyclic waveforms. We demonstrate the device's capability by quantifying intracellular calcium dynamics and cell traction forces in primary human airway smooth muscle cells under mechanical stretch. This platform provides a versatile tool for investigating the effect of mechanical cues on cellular function in both healthy and disease-relevant contexts.