Particulate leaching improves spheroid formation in PEG and gelatin-based matrices for 3D tumor model

Abstract

Spheroids have been developed and used as in vitro tumor models for various applications. However, the most commonly used hanging drop and liquid overlay methods to culture spheroids are challenging due to lack of sturdiness and reproducibility of spheroids and poor microenvironment mimicking features such as matrix stiffness and 3D architecture. Consequently, scaffold-based platforms to culture spheroids have gained momentum. It is already well established that scaffold features such as architecture, surface characteristics and mechanical properties influence the formation of spheroids. In present study, polyethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA) based scaffolds were fabricated to provide a 3D microenvironment for melanoma spheroids, and pore size of scaffolds was found to be an important parameter influencing the spheroid size. In this study, we have demonstrated that fabricating matrices using a combination of particulate leaching using sodium chloride (NaCl) and freeze-drying enhances the pore size of scaffolds for subsequent formation of larger spheroids (~300 µm) required for various applications. PEGDA-GelMA matrix fabricated in this study provides a sturdy platform for scaffold-based spheroid formation and can be used for long-term culture of multicellular spheroids for development of in vitro tumor models.