Nondestructive determination of Young’s modulus of alginate hydrogels using a soft magnetorheological elastomer-based actuator

• Magnetorheological Elastomers (MREs) were prepared by mechanically mixing and curing micro-sized carbonyl iron particles (CIP) and Ecoflex 00–30 matrix in varying mass proportions. • Cylindrical-shaped 30 wt% CIP MRE was chosen as an actuator for the compression of the prepared alginate hydrogel samples (0.5, 1 and 2 wt%). • Experimental data was assessed by the Tatara contact mechanic’s model to determine the Young’s modulus and validated by an AFM. • Results indicate enhanced mechanical strength with increase in alginate concentrations. • A simple prototype was designed and fabricated that demonstrates the ability to characterize soft biomaterials without rupturing. Hydrogels are biocompatible materials with tunable swelling and mechanical properties adaptable to biomedical applications such as drug delivery, wound healing, and tissue engineering. However, developing and optimizing hydrogels for specific uses necessitates precise adjustments to their mechanical properties, highlighting the need for efficient testing methods. Current techniques for mechanical characterization, such as atomic force microscopy (AFM), are low-throughput, complex, and expensive, limiting their suitability for high-throughput measurements essential in hydrogel development. Here, soft magnetorheological elastomers (s-MREs) comprising of carbonyl iron particles (CIP) and Ecoflex 00–30 in varying mass proportions were fabricated and characterized magnetically and mechanically. Ionically crosslinked alginate hydrogels with 0.5%, 1% and 2% polymer concentrations were prepared for experimental tests. An s-MRE consisting of 30 wt% CIP was used to conduct the mechanical characterization of the hydrogels via compression testing revealing consistent results with AFM. This characterization technique offers simplicity and cost-efficiency in comparison to existing methods. Additionally, a simple user-friendly prototype for rapid mechanical characterization of soft gels has been designed, fabricated and demonstrated, which can potentially serve as a tool for the efficient evaluation of soft materials in biomedical and industrial applications.