Synthesis and Characterization of Gelatin Methacryloyl

The detailed experimental procedure has been described previously48 (link). In short, type A gelatin (175 bloom) derived from porcine skin tissue was dissolved in CB buffer (0.1 M buffer comprising 3.18 g sodium carbonate and 5.86 g sodium bicarbonate in 1 L distilled water), and the pH was adjusted with 5 M sodium hydroxide or 6 M hydrochloric acid. Subsequently, MAA (94%) was added to the gelatin solution under magnetic stirring at 500 rpm. The reaction proceeded for 3 h, and then the pH was readjusted to 7.4 to stop the reaction. After being filtered, dialyzed, and lyophilized, the samples were stored at −20 °C until further use. The standard conditions of the synthesis were: CB buffer at 0.25 M, initial pH adjustment at pH 9, MAA amount at 0.1 mL per gram of gelatin concentration at 10 w/v%, reaction temperature at 50 °C and reaction time for 3 h.
In performing detailed characterization of the synthesized GelMA scheme, the following experimental parameters were investigated: CB molarities (0.1, 0.25, 0.5, 0.75, and 1 M), initial pHs (pH 8, 9, 10, and 11), MAA/gelatin feed ratios (MAA/gelatin: 0.0125, 0.25, 0.5, 0.1, and 0.2 mL/g), gelatin concentrations (1, 2.5, 5, 10, and 20 w/v%) and reaction temperatures (35, 40, 45, and 50 °C).