Photoluminescence Studies of DoF Effect on the Photopolymerization Reaction of a GelMA-Based Monomers for Tissue Engineering

Here, methacrylated gelatin (GelMA) is obtained at different methacrylate anhydride concentrations (5.8% and 10% v/v), different reaction times (1 and 3 h), and under pH control. A ninhydrin test and nuclear magnetic resonance are used to determine the degree of functionalization (DoF) of the samples showing that pH controlling produces better functionalization degrees than an increase in methacrylate anhydride concentration or longer reaction times. The photopolymerization process of GelMA samples is studied by time-resolved photoluminescence at different photoinitiator (PI) concentrations: 0.5%, 1%, and 2% w/v. An increase in PI concentration and DoF produces changes in the cross-link. The 2% w/v concentration produces a higher reaction speed in the first 10 min and requires longer times to end the reaction. No significant differences are found in the use of smaller concentrations. Changes in luminescent emission of GelMA are used to explore the photopolymerization reaction kinetics. The overlap of tyrosine amino acid molecular orbitals shifts the emission from the blue region to the green region. Here, luminescent emission intensity is recorded in time, allowing its correlation with the cross-linking process and the obtention of the total irradiation time. image