Self-healing properties of hydrogel. To evaluate self-healing properties of r2 hydrogels after extrusion, hydrogel precursor components were first mixed in a syringe mixing system and kept for curing in the syringe for 48 h at room temperature. Afterwards, the crosslinked hydrogel in the syringe was extruded and cast between two glass slides that were separated by a 1 mm spacer and cured overnight in a humid atmosphere and then stored in PBS for 3 days at room temperature. To study viscoelastic properties of reformed hydrogels, dynamic oscillatory amplitude sweep was performed using an 8 mm parallel plate stainless steel geometry under a constant axial load of 100 mN, at 1 Hz and compared with r2 hydrogels that were extruded immediately from the syringe mixing system after mixing of the components, kept in the mold for 3 days, followed by incubation in PBS for 3 days before subjecting to rheological amplitude sweep.