Rationally designed β-cyclodextrin-crosslinked polyacrylamide hydrogels for cell spheroid formation and 3D tumor model construction.

In vitro tumor models are essential for understanding tumor behavior and evaluating tumor biological properties. Hydrogels that can mimic the tumor extracellular matrix have become popular for creating 3D in vitro tumor models. However, designing biocompatible hydrogels with appropriate chemical and physical properties for constructing tumor models is still a challenge. In this study, we synthesized a series of β-cyclodextrin (β-CD)-crosslinked polyacrylamide hydrogels with different β-CD densities and mechanical properties and evaluated their potential for use in 3D in vitro tumor model construction, including cell capture and spheroid formation. By utilizing a combination of β-CD-methacrylate (CD-MA) and a small amount of N,N'-methylene bisacrylamide (BIS) as hydrogel crosslinkers and optimizing the CD-MA/BIS ratio, the hydrogels performed excellently for tumor cell 3D culture and spheroid formation. Notably, when we co-cultured L929 fibroblasts with HeLa tumor cells on the hydrogel surface, co-cultured spheroids were formed, showing that the hydrogel can mimic the complexity of the tumor extracellular matrix. This comprehensive investigation of the relationship between hydrogel mechanical properties and biocompatibility provides important insights for hydrogel-based in vitro tumor modeling and advances our understanding of the mechanisms underlying tumor growth and progression.