Alizarin-based soybean oil materials for the synthesis of 3D-photoprinted objects with efficient antibacterial properties.

A biobased hydroxyanthraquinone dye derived from alizarin (AA) was shown to be an efficient visible-light photosensitizer for iodonium salt (Iod), enabling high acrylate conversions (around 80%) up to 470 nm through a type II photoinitiation mechanism. Fluorescence, laser flash photolysis experiments and electron paramagnetic resonance (EPR) studies confirmed triplet-state interactions and the formation of highly reactive initiating radicals (phenyl derived radicals), leading to the synthesis of photoinduced antibacterial biomaterials. The AA/Iod photoinitiating systems exhibited high reactivity towards acrylate bonds of soybean oil acrylate (SOA), while the incorporation of geraniol significantly reduced linear shrinkage, according to photorheological tests, without compromising processability. Interestingly, both formulations (AA/Iod/SOA and AA/Iod/geraniol/SOA) were successfully applied for high-precision 3D-Digital Light Processing (3D-DLP) under visible LED irradiation. The resulting photoinduced biomaterials displayed tremendous antibacterial properties against Staphylococcus aureus and Escherichia coli, resulting from the combined effects of the in situ photogeneration of reactive oxygen species (ROS) similar to the photodynamic therapy (PDT) and geraniol diffusion. Overall, this synergistic, biobased photoinitiating system enables the synthesis of effective visible light-responsive antibacterial materials.