A soft sensor-integrated cell stretching device for precise and reproducible mechanotransduction

Mechanical stretch is a fundamental regulator of cell fate, yet in-vitro
replication remains challenging because conventional stretchers deliver
non-uniform strain and ignore batch-to-batch variations in substrate
stiffness—so the stress actually experienced by cells varies
unpredictably. We introduce the first biaxial cell-stretching platform
that couples an embedded soft resistive micro-channel sensor with
high-frequency closed-loop control. Real-time deformation read-out (60 Hz)
drives a 24 kHz actuator loop to compensate for PDMS moduli spanning an
order of magnitude, delivering user-defined triangular or square waveforms
(5–20 % amplitude; 0.5–10 s period) with < 2 % steady-state error.
Closed-loop operation maintains strain-invariant membrane stress within ±
5 %, reducing well-to-well variability three-fold compared with open-loop
actuation. Biological validation using immortalized human myoblasts
exposed to 10 % cyclic stretch for 4 h produced a significant
up-regulation of YAP/TAZ target genes (C-MYC, MYL9, DIAPH1, ANKRD1; p
< 0.001), confirming mechanotransductive efficacy. The platform’s
modular architecture accommodates stiffness-tunable hydrogels and live
imaging, offering a reproducible tool for mechanobiology, tissue
engineering, disease modelling and personalised mechanotherapy.