Methacrylated zein as a novel biobased macro-crosslinker for PVCL hydrogels

The use of natural proteins to provide novel biocompatible and biodegradable materials, by combining synthesis simplicity and suitable functional properties, is a current challenge. This article pursues the chemical modification of zein, a hydrophobic protein of corn, to obtain a radical-polymerizable zein-based building block, which is then used as a bio-macro-crosslinker for synthesizing thermoresponsive polyvinylcaprolaptam-based hydrogels. Chemical conjugation of zein is a difficult task since it only presents some few nucleophilic groups. We found that zein modification can be achieved with glycidyl methacrylated in ethanol enriched water solutions, and we showed that the degree of methacrylation can be tuned not only by the molar ratio of reagents but also by changing the solvent polarity. Zein based PVCL hydrogels presented bigger porous size, higher swelling capability, faster shrinking kinetics and better mechanical properties when they are compared to those obtained with a low molar mass crosslinker as N,N′- methylenebisacrylamide. • Biobased polymerizable building block from zein, a maize protein. • Methacrylated zein is employed as bio-macro-crosslinker of poly( N -vinylcaprolactam) hydrogel. • Bio-macro-crosslinker performance and its comparison with a low molecular weight one. • Synthesis of fully protein-based photo-crosslinked material.