A facile approach to construct ferroferric oxide/chitosan composite scaffolds with three-dimensional oriented structure has been explored in this research. Chitosan and ferroferric oxide are co-precipitated by using an in situ precipitation method, and then lyophilized to get the composite scaffolds. XRD indicated that Fe304 was generated during the gel formation process, and increasing the content of magnetic particles could destruct the crystal structure of chitosan. When the content of magnetic particles is lower than 10%, the layer-by-layer structure and wheel spoke structure are coexisting in the scaffolds. Increasing the content of magnetic particles, just layer-by-layer structure could be observed in the scaffolds. Ferroferric oxide particles were uniformly distributed in the matrix, the size of which was about 0.48 gm in diameter, 2 gm in length. Porosity of magnetic chitosan composite scaffolds is about 90%. When the ratio of ferroferric oxide to chitosan is 5/100, the compressive strength of the material is 0.4367 MPa, which is much higher than that of pure chitosan scaffolds, indicating that the layer-by-layer and wheel spokes complex structure is beneficial for the improvement of the mechanical properties of chitosan scaffolds. However, increasing the content of ferroferric oxide, the compressive strength of scaffolds decreased, because of the decreasing of chitosan crystallization and aggregation of magnetic particles as stress centralized body. Another reason is that the layer-by-layer and wheel spokes complex structure makes bigger contributions for the compressive strength than the layer-by-layer structure does. Three-dimensional ferroferric oxide/chitosan scaffolds could be used as hyperthermia generator system, improving the local circulation of blood, promoting the aggradation of calcium salt and stimulating bone tissue regeneration.
Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.
