Table 1. Comparison of collagen scaffolds and CMC-PEG gels.

Material	Origin	Preparation	Sterilization	Manipulation	Washability	Variability
Collagen scaffolds	Natural (bovine collagen)	Disintegration → freeze-drying → cross-linking → freeze-drying	Ethylene oxide or gamma irradiation	Tweezers	Continuous experiments possible–scaffolds are washable and transferrable	Variable–each material has slightly different pore distribution and orientation; an unknown number of cells successfully seeded in the scaffolds (cell losses due to cells partly flowing outside the scaffold)
CMC-PEG gel	CMC–natural; PEG–synthetic	Powder + H2O → 120-140 °C for 30 min	UV light	Weighing, wide-bore tip pipetting	Difficult to wash (all additives mostly remain in the gel)	Each material displays the same features; a known number of cells seeded into the gel

Note:

Washability refers to the ability of materials to be washed after exposure to a substance, which is non-toxic for a short period of time but can be toxic after long-exposure (e.g., AlamarBlue).