Studies On The Properties And Applications Of The Electrospun Membranes Composed Of Gelatin And Poly(ε-caprolactone)

Over the past decade, electrospinning has gained tremendous attention due to its simple, convenient, repeatability, continuity and extensibility etc. Most polymers could be electrospun to micro-nanoscale fiber. Electrospun fibers are notable for their ultrafine diameter and large surface area-to-volume ratios, especially mimicking of the ECM, which enable them to be tailored for a multitude of applications in biomedical fields. Different properties of electrospun membranes are required with regard to specific application. While the properties of electrospun membranes are mainly depending on the composition of fiber and the structures. Nowadays, studies are focusing on the structures such as fiber diameter and arrangement that might arouse the difference of electrospun membranes" properties. It is import that attentions should be paid to fiber structures as hybrid membranes concerned. To elucidate the effect of fiber structure on the properties of the hybrid membranes, the crystalline characteristics, Gt swelling, wettability, and mechanical strength of the electrospun hybrid membranes prepared by different electrospinning methods (C-1、C-2、C-3, B-1、B-2、B-3,M-1、M-2、M-3) were systematically compared. It was found that the crystalline characteristics of PCL in the core-shell fibers were different from the fibers fabricated by the other two methods. That is, the orientation degree of the PCL chains in the core-shell fibers was higher than that in both blend and mixed fibers. The wettability of the hybrid membrane was dependent on both the composition and structure of the electrospun fibers. Core-shell fibers possessed hydrophilic due to Gt was the shell. Blended fibers exhibited the highest hydrophobicity because of the enrichment of PCL at the fiber surface. The contact angle of B-2was even with pure PCL membrane. And the mixed fibers possessed the highest mechanical strength. Tensile strength was3-5.18MPa and2.5-3.5MPa under dry and wet condition, respectively. These results revealed that the properties of hybrid membranes are affected by fiber structures remarkably. The cytotoxicity of hybrid membranes was investigated by NIH-3T3. The results showed that the cytotoxicity of hybrid membranes was very low and the effect of fiber structures on the cells behavior was unobvious.Furthermore, in order to overcome drawback of crosslinker for gelatin, the feasibility of utilizing PA as acrosslinker of the electrospun gelatin membranes was evaluated. The effect of different crosslinkers including glutaraldehyde, genipin and procyanidine on the properties of the electrospun gelatin membrane, such as the morphology, mechanical strength, enzymatic degradation and cell behavior, was systematically compared. The water-resistant ability of the membranes could be significantly improved after being rosslinked with PA at T>40℃. In contrast with GTA and GIP, the PA-crosslinking process did not apparently affect the fibrous structure, and induced the lowest shrinkage of the membranes. At the concentration of5%of PA, the ultimate tensile strength and elongation of the hydrated membrane were0.87MPa and148%, respectively, which were higher than those of the GIP-crosslinked counterparts. In addition, the PA-crosslinked membranes displayed the highest resistance to pepsin degradation, and fibroblast cells could migrate deeper into the interior of the membranes due to the good preservation of the fibrous structure during the cell culture process. Meanwhile the electrospun Gt membranes for wound healing were investigated.