Sponge-like Scaffolds for Colorectal Cancer 3D Models: Substrate-Driven Difference in Micro-Tumors Morphology

Abstract

Macroporous scaffolds (cryogels) for the 3D cell culturing of colorectal cancer micro-tumors have been fabricated by cross-linking chitosan and carboxymethyl chitosan (CMC) with 1,4-butandiol diglycidyl ether (BDDGE) under subzero temperature. Due to the different intrinsic properties and reactivity of CMC and chitosan under the same cross-linking conditions, Young′s moduli and swelling of the permeable for HCT 116 cells cryogels varied in the broad range 3–41 kPa and 3500–6000%, respectively. We have demonstrated that the morphology of micro-tumors can be controlled via selection of the polymer for the scaffold fabrication. Although both types of the cryogels had low cytotoxicity and supported fast cell proliferation, round-shaped tightly packed HCT 116 spheroids with an average size of 104 ± 30 µm were formed in CMC cryogels (Young′s moduli 3–6 kPa), while epithelia-like continuous sheets with thickness up to 150 µm grew in chitosan cryogel (Young′s modulus 41 kPa). There was an explicit similarity between HCT 116 micro-tumor morphology in soft (CMC cryogel) or stiff (chitosan cryogel) and in ultra-low attachment or adhesive culture plates, respectively, but cryogels provided the better control of the micro-tumor’s size distribution and the possibility to perform long-term investigations of drug–response, cell–cell and cell–matrix interactions in vitro.