In an earlier study with chemically crosslinked injectable collagen hydrogel, we demonstrated that hydrogel moduli can be very easily fine-tuned by controlling the number of covalent crosslinks formed through varying the stoichiometry between reaction partners. Although this is trivial for hydrogels prepared using synthetic polymer, such as polyethylene glycol, with low molecular weights where covalent crosslinks are the sole determinants of elasticity, this is not the case for ECM-polymer based hydrogels where elasticity also originates from the self-assembly of polymer chains as well as chain entanglements. Earlier studies involving native telopeptide-rich collagen and matured telopeptide-poor collagen revealed more chain entanglements in case of telopeptide-rich collagen. Since the collagen used in our studies is telopeptide-poor, it is rational to assume that there will not be much chain entanglements in the crosslinked hydrogels from collagen or from the PEG since the molecular weight of the PEG is low. However, the collagen will tend to assemble leading to elastic contribution and it could be impossible to fine-tune the collagen hydrogel moduli by only varying the covalent crosslinks. This was found to be true in one of our earlier studies. However, in an effort to fine-tune the hydrogel moduli, different stoichiometric ratios of furan to maleimide were investigated using oscillatory rheology (Figure ). With increasing the furan to maleimide ratio from 1 to 2, the G´ (3245±218 Pa vs 4010±165 Pa) and G´´ (380±23 Pa vs 463±37 Pa) increased further (p < 0.05); however, further increasing of maleimide to furan ratio has no significant effect on G´ and G´´ values, (Figure and). The loss tangents were found to have no statistically significant differences among various formulations (Figure D).