In vitro biological evaluation. Three different cell lines were embedded into GG, GG_HA_Coll_high and GG_HA_MCollB_high hydrogels: BALB-3T3 cells (A) and (B); RAW 264.7 cells (C) and (D), C2C12 (E–H). (A) BALB-3T3 LIVE/DEAD® assay to assess cell viability at 1, 3 and 7 days. (B) BALB-3T3 proliferation evaluation up to 7 days of culture. (C) RAW 264.7 cell viability analysis at 48 h. (D) RAW 264.7 gene expression profile relative to M1 (IL-1β and TNF-α) and M2 (IL-10) phenotype at 48 h. (E–F) C2C12 LIVE/DEAD® assay at day 1 and day 7 (F). (G–H) C2C12 cell morphological analysis staining, (H) merge of brightfield, actin and dapi; * indicate MCollB. Scale bars: (A, E, F) 250 μm; (G) 20 μm; (H) 15 μm. Statistical analysis: *p value ≤ 0.05, **p value ≤ 0.01, ***p value ≤ 0.001 and ****p value ≤ 0.001.