Clean modification of potato starch to improve 3D printing of potential bone bio-scaffolds

Although the 3D printing of biomaterials has witnessed remarkable advancements, there is still a need to develop appropriate bio-based inks. Starches are interesting alternatives to produce hydrogels to be used as inks, but native starches rarely present good performance in 3D printing. To bridge this gap, our study innovatively explores new avenues for the utilization of natural biopolymers in biomedical applications. In this sense, we applied the dry heating treatment (DHT) as a "clean" method to modify potato starch for use in the 3D printing of bone bio-scaffolds. Firstly, the effect of the DHT (1, 2, and 4 hours at 130 °C) process was evaluated on the structure and physicochemical properties of starch and their hydrogel. Then, 3D-printed bio-scaffolds were obtained from the hydrogels and evaluated in relation to their mechanical performance. DHT promoted starch molecule oxidation and partial depolymerization. The molecular changes resulted in new properties for the obtained hydrogels, such as firmness, cohesion energy, storage modulus (G'), and improved 3D printability – with better accuracy and geometry fidelity. The 3D-printed bio-scaffolds based on DHT starches showed a reduction in the biodegradability rate in relation to the native starch, reducing the swelling power, and improving the mechanical performance – in special DHT 130 °C for 1 h. In conclusion, the DHT process is a "clean" and effective method to modify potato starch not only to enhance the performance of the hydrogels but also to improve the properties of the printed biomaterials.