In this thesis, Cu₂O nanochains were synthesized by thermal decomposition with copper formate-octylamine as the precursor, oleic acid and oleylamine as the catalyst stabilizer agent and paraffin as the solvent. The phase structure and micromorphology of Cu₂O nanochains were characterized by X-ray diffraction and transmission electron microscopy. The effect of reaction time and concentration of the precursor on the Cu₂O nanochains were discussed, and the formation mechanism of the Cu₂O nanochains was analyzed. The results show that Cu₂O nanochains were self-assembled by Cu₂O nanocrystals; with the extension of the reaction time, Cu₂O nanochains gradually become granular; increasing the concentration of the precursor will increase the entanglement degree of the nanochains. Oleic acid contributes to the formation of Cu₂O, and oleylamine plays a directional role in the formation of nanochains. On the basis of those phenomenon, a comparison of the Cu₂O nanochain-water nanofluids with that of a water-based liquid showed that after irradiating for 3000 s, the temperature of nanofluids reached 91.1 °C while the water was only 75.7 °C. This demonstrates the better performance of the Cu₂O nanochain-water nanofluid in the ability of light absorption, thermal conductivity and photothermal conversion.

3D bioprinting is an emerging research field developed by the deep cross-fertilization of 3D printing technology with multiple disciplines such as mechanics, materials, and biomedicine. Extrusion 3D bioprinting, the most widely used 3D bioprinting technology, can print biomaterials with different viscosities and has a wide range of material applicability. In this study, we prepared a composite hydrogel with gelatin-oxidized nanocellulose as the matrix and glycerol as a multifunctional co-solvent, and the optimal composition of the hydrogel was determined by material characterization. The microstructure of the hydrogel was visualized by scanning electron microscopy (SEM), and it can be seen that the composite hydrogel material has a three-dimensional porous network structure with microporous pore sizes ranging from 200–300 µm. The infrared spectra also showed that the addition of glycerol did not interact with gelatin-oxidized nanocellulose while improving the hydrogel properties. Meanwhile, the composite hydrogel has obvious shear-thinning properties and good mechanical properties, which are suitable for extrusion-based 3D bioprinting, and the printed area is clear and structurally stable. A series of results indicate that the hydrogel is suitable for extrusion-based 3D bioprinting with good pore structure, mechanical properties, and printable performance. This gelatin-oxidized nanocellulose hydrogel provides a new idea and material for 3D bioprinting and expands the potential uses of the material.