Exploiting Response Surface Methodology to Engineer the Mechanical Properties of Alginate-based Hydrogels

Engineering human tissue microenvironments that recapitulate the composition and biomechanics of extracellular matrix (ECM) in vitro is challenging. New mechanically tunable alginate-based hydrogels are presented, enabling to precise model multiple ECM features in the context of breast cancer. Combining alginate, oxidized alginate (OA), and gelatin with different crosslinking strategies a library of mechanically controlled hydrogels supporting human cell growth (MDA-MB-231) is obtained. The compressive moduli and stability of alginate-based hydrogels are characterized and modeled using a response surface methodology (RSM); this enables to selection of precision-hydrogels decoupling their biochemical composition with mechanical properties (1–30 kPa). Specific alginate-based hydrogels are selected as enhanced technologies to model breast-specific microenvironments in vitro to study the impact of biomechanical and biochemical properties on cell behavior. Doxorubicin is selected as a model drug and as first-line treatment for breast cancer to investigate the correlation between drug efficacy and breast tumor ECM stiffness. Results demonstrate that doxorubicin is less effective (EC₅₀ 0.495 µm vs EC₅₀ 0.189 µm) in cells cultured in softer hydrogels (6.9 kPa) than in stiffer (21.0 kPa). In the context of breast cancer, engineered hydrogels prove valuable technologies to model tissue-specific ECM in vitro for biological studies, advancing understanding of therapeutic response and resistance.