New Class Of Human Collagen - Chitosan Electrospun Nanofiber Structure Of Tissue Engineering Scaffold And Research

A novel human-like collagen (HLC)/chitosan complex nano-fibrous scaffold was fabricated by electrospinning for the first time. The morphology of obtained meshes was determined by SEM and the conditions to successfully electrospin HLC and chitosan in aqueous solutions were also researched by studying the influence of the properties of polymer solutions on the electrospinning process and results. It was found that the arrangement of polymer molecules in solutions played the key role for electrospin, and it was the entanglement and slide between long molecular chains in proper solvents in which polymer moleculars could extent fully made electrospin possible. Pure HLC aqueous solutions could not be electrospin since the molecular weight of HLC was too low and the molecular chain was too short; and pure chitosan could not be electrospin either in acetic acid aqueous solutions due to the strong interactions within moleculars caused by the hydrophobic effect and the hydrogen bond, which forbid the entanglement and slide between molecular chains. The addition of PEO with high molecular weight could change the alignment of HLC or chitosan molecules in aqueous solutions by offering long axle for entanglement and breaking the strong interactions of the polycationic chitosan molecules, thus make HLC and chitosan solutions suitable for electrospin. The ATR-FTIR testing demonstrated that PEO would be easily removed by rinse and was a suitable additive for electrospin. This research developed the instructive theory for all the biomaterials to electrospin for the first time and also made the fundamental research to electrospin complex solutions of hydrophilic and hydrophobic polymers.Bead-free nano-fibrous meshes were fabricated successfully by electrospinning different HLC/chitosan aqueous solutions after adding PEO. The diameters of obtained nano-fibers ranged from 112±35 nm to 413±62 nm. In the process of cross-linking it was found that only when the total concentration of HLC and chitosan reached 4 folders of PEO, the meshes would not dissolve and break into slices in water. The diameters of fibers would increase after cross-linking and the groups which didn't contain chitosan would lose the fibrous structure leaving only fibrous trace. TG analysis showed that the meshes after cross-linking were more stable to heating. Among the groups containing both HLC and chitosan, group G had the most homogenous morphology, with the ultimate tensile strength of 630±23 kPa, tensile elongation of 13±0.2% and the Young's modulus of 5.5±0.13 MPa. The in vitro and in vivo degradation tests, cell culture and biocompatibility testing showed that the complex membranes of group G could facilitate cell adhesion and proliferation, have excellent biocompatibility and proper degradation rate. These all demonstrated that membranes of complex membranes of group G could mimic both the constituent and structure of native extra-cellular matrix (ECM), and had the potential to use in tissue engineering application.