Application Of Atmospheric Pressure Plasma Jet In Surface Modification Of Poly(L-Lactic)Acid Oriented Fibrous Membrane

Tissue engineering is an emerging discipline for researching and developing to repair human tissue or damaged organs.Among them,the selection and preparation of tissue engineering scaffold materials is particularly important.Poly(L-Lactic)Acid(PLLA)is widely used in tissue engineering for its excellent biodegradability and good mechanical properties.Compared with the traditional membrane structure of PLLA,the oriented three-dimensional porous PLLA fibrous membrane not only can simulate the structure and function of the extracellular matrix,but also can contact and guide cell growth and promote cell arrangement,so it has received more and more attention in recent years.Therefore,PLLA is prepared into an oriented fibrous membrane structure.However,the hydrophobicity of the PLLA oriented fibrous membrane results in poor cell affinity,which is detrimental to cell adhesion and proliferation.The atmospheric pressure plasma jet(APPJ)is rich in a variety of reactive functional groups that can surface modify different biomaterials to improve the hydrophilicity and biocompatibility of biomaterials.APPJ has the advantages of simple structure,low cost,flexible operation and friendly environment.It is not limited by physical space when modified with APPJ and is suitable for three-dimensional material modification.Moreover,APPJ is produced at low temperature and can be used for surface modification of heat-sensitive polymer materials.Based on the modification principle of atmospheric pressure plasma jet,the modification process of PLLA oriented fibrous membrane was studied,and gelatin was fixed on the basis of this to further improve the biocompatibility of the sample surface,finally,cell culture was carried out on the surface of gelatin-fixed samples to study the effects of APPJ surface modification and gelatin fixation on cell proliferation and morphology.The main research contents of this thesis are as follows:1.The preparation method of PLLA oriented fibrous membrane was studied,and the morphology of the fibrous membrane was characterized by scanning electron microscopy(SEM)and the fiber diameter was statistically analyzed by Image J to prepare an oriented fiber membrane with an average fiber diameter of 675±11 nm.2.The electrical and emission spectrum characteristics of the self-made APPJ device were studied,and the PLLA oriented fibrous membrane was surface-modified with He/O2 APPJ.Then,the gelatin biomolecule was immobilized on the surface of the APPJ modified sample by graft-coating method to further improve its biocompatibility.The effects of different APPJ treatment time,different working voltages and different He/O2 mixing ratios on the modification results were investigated,and the parameters were optimized.3.The mouse myoblast C2C12 was inoculated on the surface of PLLA-oriented fibrous membrane before,after APPJ modification and after gelatin fixation,and the cell proliferation under different APPJ treatment time and different cell culture time was studied.The cells growth morphology on the surface of the sample was observed by scanning electron microscope.The results show that C2C12 cells have a more spread morphology and a larger growth density on APPJ-modified and gelatin-immobilized oriented fibrous membranes compared to untreated oriented fibrous membranes.