Fig. 1

Seaweed derived from green marine macroalgae species (A-C) Ulva sp. and (D-F) Cladophora sp. Imaging of (A, D) fresh seaweed thallus before decellularization. Macro view of decellularized SC scaffolds reveal (C) Ulva sp. with highly organized porous architecture and (D) Cladophora sp. with highly fibrous architecture. (E, F). Hematoxylin and eosin (H&E) staining cross-sections of seaweed after decellularization reveal eosin stain of the matrix and no hematoxylin (cell nucleus). (G) DNA quantification analysis using a NanoDrop spectrophotometer, reveal DNA concentration of fresh (f) and decellularized (d), Ulva sp. (U) and Cladophora sp. (C) seaweed samples, confirming both scaffolds as acellular post decellularization. Additionally, closeup SEM imaging of (H) decellularized porous Ulva sp. and fibrous Cladophora sp. and (I) fibroblast, 4 weeks post recellularization, reveal Cell–Matrix interactions, and the impact of SC scaffold structural properties on cell morphologies and spreading. Ulva sp. facilitate stretched morphologies and 2D spreading opportunities in all direction, while the Cladophora sp. facilitate spindle morphologies and 1D spreading opportunities along the fiber elongated axis. (J) Representative plots of fibroblast cell size post recellularization. (K) summarized information Table for each SC scaffold and cells features. Correlation between the SC matrices and the fibroblast behavior, with significant difference between the two scaffolds, demonstrating fibroblast cell size larger than the Ulva sp. pore size, while smaller than the Cladophora sp. fiber width impact cell behavioral tendencies. Scale Bar: *Scale Bars: (A) = 5 cm, (B) = 0.5 cm, (C, D) = 50 µm, (E, F) = 100 um, (H) = 5 µm, (I) = 10, 20 µm, (Bar-Shai, et al. 2021).