Ethanol precipitation with cooling enables rapid purification of gelatin methacryloyl (GelMA) with increased yield and preserved solution-state organisation

Abstract

Gelatin methacryloyl (GelMA) is a widely used photocrosslinkable biomaterial, yet routine laboratory synthesis is constrained by multi-day dialysis required to remove cytotoxic methacrylic anhydride (MAA) and methacrylic acid (MA). Here we introduce a simple post-reaction precipitation of GelMA in ethanol (EtOH) as a faster purification route. EtOH precipitation combined with cooling increased the isolated yield after purification (up to + 17.5% versus the control) and markedly accelerated impurity removal, reaching commercially relevant residue benchmark (< 30 ppm) within 2 days, whereas the conventional route required 7 days under identical dialysis conditions. Importantly, CD and SEC indicated that prolonged dialysis altered GelMA solution-state organization while EtOH precipitation followed by only 2 days of dialysis better produced material more similar to the parent gelatin. Hydrogels prepared from control and EtOH-treated GelMA displayed comparable swelling, rheology, compressive response, and indirect cytocompatibility with MC3T3-E1 cells. This accessible EtOH-assisted workflow reduces purification time without sacrificing functionalization or hydrogel performance and may improve batch-to-batch consistency for laboratory-scale GelMA production.