Tumor spheroid formation in several types of cancer cells in Matrigel, collagen I, and designer peptide hydrogels.[
142
,
170
,
223
] A) SMMC7721 cells. B) MDA‐MB‐231S stem‐like cancer cells (reproduced with permission, copyright 2015, Dove Press); In Matrigel, both SMMC7721 cells and MDA‐MB‐231S stem‐like cancer cells form regular tumor spheroids when cultured for 3 d or 5 d (left panels). In collagen I, both SMMC7721 cells and MDA‐MB‐231S stem‐like cancer cells cannot form regular tumor spheroid growth pattern, but grow in a stretched cell shapes (middle panels); In RADA16‐I peptide hydrogel, except of MDA‐MB‐231 cells, both SMMC7721 cells and MDA‐MB‐231S stem‐like cells form regular tumor spheroid growth pattern (right panels). C) A546 lung cancer cells; when seeded on different EFK8 hydrogels, tumor spheroidal colony growth pattern is formed in 1.25 mg mL−1 EFK8 peptide hydrogel, 5.0 mg mL−1 EFK8 peptide hydrogel, and 1.25 mg mL−1 EFK8‐SWNT hybrid hydrogel (adapted with permission.[
196
] Copyright 2018, Elsevier Ltd).