Novel Chitosan Bioink Derived from Eurycantha calcarata (Lucas, 1869) for 3D Bioprinting of Cell-Compatible Scaffolds

Three-dimensional (3D) printing of eco-friendly, naturally derived biopolymers such as chitosan offers great potential for biomedical applications. In this work, Eurycantha calcarata insects were used as the source of chitosan with a yield of 22.2% and a deacetylation degree of 77–78%, comparable to that of commercial chitosan. After extraction, characterizations were performed on the obtained compound (including FTIR, NMR, SEM, TGA, and XRD). Formulated into chitosan:gelatin hydrogels (EC:G = 1:3, 1:4, 1:5), the blends exhibited solid–liquid transitions at 29–33 °C depending on gelatin content. 3D-printed scaffolds achieved >90% shape accuracy and remained stable for 21 days in a culture medium. HeLa cells cultured on the scaffolds showed up to 99.6% viability after 3 days, demonstrating excellent cytocompatibility. By valorizing insect-derived waste, this work presents a sustainable and high-performance chitosan bioink, addressing the growing demand for eco-friendly materials in 3D bioprinting.