Ozonation as a green modification for potato and cassava starches in 3D-printed bone scaffolds

Tissue engineering increasingly explores plant-based hydrogels for their biocompatibility and low cost. Starch is a promising option for 3D extrusion printing, but its weak mechanics and rapid degradation require modification. Ozonation offers a sustainable strategy to improve starch functionality, since excess ozone decomposes into oxygen. Combined with additive manufacturing, it enables printing of 3D structures suitable for tissue regeneration. This study evaluated ozone-modified potato and cassava starches for bone tissue engineering. Native starches were oxidized and analyzed for structural, molecular, and rheological changes. Ozonation produced carbonyl groups (0.17 and 0.19 units/100 glucose units for potato and cassava) and carboxyl groups (0.11 and 0.10 units/100 glucose units), reduced crystallinity (2% in potato), and generated uniform lower-molecular chains (polydispersity <1.6). Rheological tests showed stronger pseudoplastic behavior (tan δ < 0.09), improved viscoelasticity, and higher gel cohesion, especially for cassava (3.7-fold increase), enabling greater printing precision. Functional tests showed reduced swelling (1.5-fold for potato, 2.3-fold for cassava), enhanced biodegradability (cassava retained 40% mass after 14 days), and improved mechanical strength, with ozonized potato scaffolds reaching 15.9 kPa. However, due to structural collapse, no mechanical data could be obtained for ozonized cassava scaffolds. Osteoblastic assays confirmed biocompatibility; cassava promoted early cell adhesion and proliferation, while potato maintained long-term viability. Overall, ozonized starches present sustainable, plant-based biomaterials for 3D-printed bone scaffolds.