Bio-inspired hydrogels comprising organic and inorganic components association explored as Bingham precursor solution for extending direct ink writing technique in 3D printing.

This study is basically, the development of Bingham precursor hydrogel-based solution for direct ink writing (DIW) for the development of 3D printed hydrogels. The hydrogel is used as a precursor solution for its promising application in artificial human organ development, flexible, and wearable strain sensor by DIW method. The development of Bingham fluid with controlled and improved fluidity, enhancing the mechanical property of extruded materials, stability, and conductivity remains challenging. Currently, we demonstrate the synthesis of hydrogel precursor solution for sensors and artificial human organs fabrication via 3D printing by DIW method to approach mechanically better and more sensitive hydrogels. In present work, the precursor solution was developed, using acrylamide (Am), gellan gum (GG), SiO2 nano-particles, and carbon nanotubes (CNTs) for potential application in healing, mechanical improvement, and sensitivity factors. This compositional mixture of various organic, inorganic fillers, and additives is optimized regarding the improve 3D printability by rheological characterization process for Bingham fluid. The critical strain (γc) within the linear viscoelastic region (LVER) improved from 14 to 46.2. Furthermore, these fabricated hydrogels have been evaluated for dynamic mechanical analysis for tensile and healing properties. By introducing SiO2 and CNTs into Am/GG co-polymeric hydrogels, the tensile strength (fracture stress) of 158.7 kPa was found with 69 kJ/m3 of toughness, which is 206 % enhancement and 0.23 kPa of elasticity (Young's modulus) having 328 % improvement then pure hydrogels. The as synthesized hydrogel was used for 3D printing of different shapes and a sensor for human motion detection. The hydrogel recovered up to 90 % of its original tensile strength after self-healing, demonstrating a strong capacity for structural restoration which mimic the self-directed repairing of minor damage of hydrogel during its routine operation.