Quantitative contrasts in the photopolymerization of acrylamide and methacrylamide-functionalized gelatin hydrogel building blocks.

The synthesis and evaluation of gelatin acrylamide as an alternative to the well-established gelatin methacrylamide are reported. High-resolution magic angle spinning NMR is used for the quantitative determination of the chemical cross-linking density. The gelatin acrylamide precursors reveal enhanced cross-linking in terms of reactivity and double bond conversion, resulting in stronger networks. Remarkably, even at very low double bond conversions, ≈5%, gel fractions of ≈40% are obtained. The cross-linked networks are also reviewed in the framework of the rubber elasticity and thermodynamic swelling theories to estimate important nanostructural properties. Preliminary cell tests revealed that highly viable (>90%) cell-laden constructs are obtained.