Non-destructive surface acoustic wave sensing for real-time material characterisation of GelMA hydrogels

Gelatin Methacryloyl (GelMA) hydrogels are widely utilized in biomedical applications due to their biocompatibility and tenable mechanical properties. Traditional methods for measuring stiffness are often destructive, which limits real-time monitoring of critical processes such as swelling and cell growth. Here, Surface Acoustic Wave (SAW) sensing is employed to characterize the mechanical properties of GelMA hydrogels with varying concentrations and degrees of functionalization. GelMA samples were fabricated and subjected to compression testing alongside SAW measurements to assess stiffness via wave attenuation. While mass load affects wave reflection linearly, wave attenuation is an exponential response and the primary influence on stiffness measurements, with SAW sensing yielding greater reproducibility than compression testing. This indicates enhanced reliability and sensitivity in measuring dynamic property changes. Rayleigh-SAW technology has been successfully applied to 3D hydrogels, enabling real-time monitoring of cellular behavior and supporting advances in tissue engineering and other biomedical applications. Overall, SAW sensing offers a promising alternative to traditional mechanical testing, enhancing our ability to analyze complex biological systems.