Ref.: MpoBi02-027
Apresentador: Samile Bezerra de Aguiar
Autores (Instituição): Aguiar, S.B.(Universidade de São Paulo - São Carlos); Araújo, R.N.(Universidade de São Paulo - São Carlos); Melo, M.T.(Universidade de São Paulo - Ribeirão Preto); Ciancaglini, P.(Universidade de São Paulo - Ribeirão Preto); Ramos, A.P.(Universidade de São Paulo - Ribeirão Preto); Maniglia, B.C.(Universidade de São Paulo - São Carlos);
Resumo:
The additive manufacturing process has been consolidating itself as a great technology for the production of materials, ranging from inorganic materials to hydrogel-based biomaterials. With a higher customization and reproducibility, the 3D printing process can be applied to develop precisely shaped polysaccharide-based scaffolds for different applications, such as bone tissue regeneration. Starch-based scaffolds, for example, can mimic bone tissue, facilitating osteoinductive cell growth. However, native starch hydrogels have limitations in terms of their rheological, mechanical properties, and functional properties. Intending to overcome these restrictions and develop 3D printed scaffolds from starch hydrogels for bone tissue regeneration, environmentally thermal modifications (dry heating treatment – DHT, and heat moist treatment – HMT) were applied, combined, for modifying cassava starch. DHMT was performed on cassava starch following both DHT and HMT treatments, respectively, while HMDT was conducted using HMT first and then DHT. For the dry heating step, the starch was modified at 130 °C for 4 h, while the heat moist step was carried out in the starch with adjusted moisture content (27%) at 100 °C for 4 h. The oxidation degree of modified starches was evaluated by carbonyl and carboxylic content, and the granules morphology was analyzed through optical microscopy. The starch hydrogels (inks) were prepared by the gelatinization of 10 % (w/w, d.b.) of starch at 85 °C for 30 min, and then stored for 24 hours in the refrigerator. The starch hydrogels were characterized in relation to firmness by penetration assay using a texturometer (TA.XT Plus Instruments) and printability by image analysis of the printed samples using Image J software. Scaffolds based on these hydrogels were printed (BioedPrinterV4, BioEdTech - Brazil) and freeze-dried, and their potential use as support materials for bone regeneration was assessed through biodegradability test and swelling behavior, as well as cytotoxicity by MTT assay using MC3T3-E1 pre-osteoblasts cells. In general, the dual modifications (DHMT and HMDT) resulted in starch granules with slight cracks and oxidation signals (superior carbonyl and carboxyl content) when compared to single modifications and the native. In addition, the dual modifications (DHMT and HMDT) show superior efficiency resulting in firmer gels (cohesion energy of DHMT 168% higher than DHT, for example) and scaffolds with reduced biodegradability and swelling capacity (less than 80% for duals, whereas for the HMT, for instance, it was 95%). All scaffolds showed no cell toxicity. Finally, the combined methodology improved hydrogel printability and the final properties of the starch-based scaffolds, enhancing the potential of these source to be used in the production of bone scaffolds by 3D printing.