Electrospinning Gelatin/Chitosan/Hydroxyapatite /Graphene Oxide Micro Pattern Composite Nanofibers

Hard tissues in nature(such as bones and teeth) have multiple complex hierarchical structures. These highly ordered microstructures provide hard tissues unique near perfect overall performance. From this, we realise the importance in preparing the kind of biological materials which could mimic natural hard tissue microstructure and excellent properties. Electrospinning is a preparation process which uses polymer solution to form micro- or nano-scale fibers under a strong electric field. Since the structure of the electrospun fiber is similar to the extracellular matrix, as a result, electrospinning is an effective method for preparing nano-scale fibers.Research has shown that by changing the surface microstructure of the collecting device one can control the spatial distribution and arrangement of the nanofibers effectively. In this paper, we prepare Gel/CS/HA/GO antibacterial composite fibers by electrospinning and patterned templates, with composition and microstructure are similar to native bone tissue. We then investigate the Gel/CS/HA/GO composite fibers’ spinning conditions and determine the optimal parameters. Next, we characterize the fibers’ morphology and performance. Specific research contents include the following parts:(1) Prepare the Gel/CS two element composite fiber membrane with microstructure and optimize experimental conditions. The results of the study show that the patterned conductive template greatly influences the distribution of fibers, and the distribution and arrangement of fibres is according to the microstructure of the template pattern. At 15% Gel(molecular weight 8000000), 3% CS(molecular weight 50000), the optimal spinning fiber is obtained.(2) Prepare the Gel/CS/HA three element composite fiber membrane and investigate its protein adsorption. The results of the study show that at 12 μm HA particle size, the optimal spinning fiber is obtained at 3% HA concentration. Moreover, by increasing p H of BSA solution, the adsorption of protein onto microstructure fibers becomes similar to the adsorption of protein onto disordered fibers. However, they have slightly different in maximum adsorption capacities. As initial concentration increases, initial adsorption increases, reaching equilibrium after 20 min. For the composite fiber with microstructures, as the initial concentration increases, the fiber’s surface protein adsorption also increases.(3) Prepare the Gel/CS/HA/GO four element composite fiber membrane with microstructure and study its performance. The results of the study show that the optimal parameters are: 15 k V voltage, 20% concentration of acetic acid, 15% concentration of Gel(molecular weight 8000000), 3% concentration of CS(molecular weight 50000), 3% concentration of HA(particle size 12 μm), and 0.05% concentration of GO. Moreover, with the increase in p H of the BSA solution, the BSA adsorption of the disordered fiber is similar to the BSA adsorption of the fiber with microstructure, but the effective area of the protein adsorption is different, which results in slightly different p H values at the maximum BSA absorption capacity. As initial concentration increases, initial adsorption increases, reaching equilibrium after 20 min. With the addition of GO, because the BSA, Gel, and GO are all negatively charged at p H 7.35, the four element composite fiber absorbs more protein than the three element composite fiber.(4) The Gel/CS/HA/GO four element composite fiber with micro structure has good antibacterial activity against Escherichia coli and Staphylococcus aureus.(5) Adding CS polymer and inorganic particles into the Gel can enhance the mechanical properties of the fiber membrane. Because the composite fiber with microstructure is anisotropic, the tensile strength of the fiber membrane with microstructure is greater than that of the disordered fiber.The above results show that we were able to prepare the Gel/CS/HA/GO four element composite fibers successfully and control their spatial distribution and arrangement accurately. It plays an important role in the field of preparing inorganic / organic composite material with controllable microstructure and excellent comprehensive properties.