Development and Characterization of a Tunable PDMS Substrate Model for Investigating Elastic Properties and Mechanical Stretching in Intervertebral Disc Cells

This study introduces a tunable PDMS substrate model for studying how elastic properties and cyclic mechanical stretching influence annulus fibrosus (AF) cell behavior in intervertebral disc (IVD) degeneration. By mixing Sylgard 184 and Sylgard 527 at varying ratios, the researchers fabricated PDMS substrates with elastic moduli ranging from 8.7 to 238 kPa, achieving physiologically relevant stiffness levels. Mechanical, optical, and biochemical characterizations showed excellent transparency, stable viscoelastic behavior, and biocompatibility with AF cells. The platform, integrated into custom stretching chambers, enables precise control of mechanical cues and stiffness, offering a cost-effective alternative to commercial STREX systems for IVD mechanobiology.