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 mu m vs EC50 0.189 mu m) 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.