Study On Preparation Mechanism And Application Of Nanofiber Membranes With Large Pore Sizes

The electrospun nanofiber membranes usually have small pore sizes,which can easily lead to cell growth restriction and is not conducive to nutrient transport and waste excretion,thus affecting its application in tissue engineering.Therefore,the preparation of nanofiber membranes with large pore sizes by electrospinning(ES)technology has become a research hotspot in tissue engineering field.In this paper,a modified ES(MES)device has been designed and developed to successfully prepare nanofiber membranes(NFMs)with large pore sizes,and the effects of different spinning parameters on the morphologies and pore sizes of NFMs with large pore sizes have been studied.The preparation mechanism has also been discussed,which provided the experimental and theoretical basis for the controllable preparation of nanofiber membrane with large pore sizes.The details are as follows:(1)A MES device,which consists of a copper mesh collector and an air pump placed behind it,was designed and developed.The mechanical analysis of the charged jet in the spinning process was carried out,and the theoretical relation equations between spinning parameters were established for the subsequent study.The results of theoretical analysis showed that the MES device can successfully prepare NFMs of large pore sizes by adjusting spinning parameters.(2)Polyvinyl alcohol(PVA)NFMs with large pore sizes were successfully fabricated by the MES device.The effects of spinning parameters,such as the grid size of copper mesh,air velocity,applied voltage,flow rate and spinning distance,on the pore sizes of PVA NFMs were investigated.The theoretical analysis were verified with experimental results,and the optimal spinning parameters for preparing NFMs with large pore sizes were determined.It was found that when the grid size of copper mesh was 4mm × 4mm,the air velocity was 5m/s,the applied voltage was 12kV,the flow rate was 1.0mL/h and the spinning distance was 18cm,the obtained NFMs have better morphology and larger pore size.(3)Polycarbonate/polyethyleneglycol(PCL/PEG)composite NFMs(CNFMs)with large pore sizes were successfully prepared by the MES device,which have better biocompatibility.The effects of PEG molecular weight,the weight ratio of PCL:PEG and the concentration of PCL/PEG mixed solute on the CNFMs were investigated by characterizing the morphology,structure and properties of the CNFMs.The results showed that when the molecular weight of PEG was 2000,PCL:PEG was 80:20,and the concentration of PCL/PEG mixed solute was 25%,the quality of CNFMs obtained was the best.(4)Cell cultures were carried out on the traditional electrospun PCL/PEG CNFMs and the modified electrospun PCL/PEG CNFMs.The morphology of cell growth on the CNFMs was characterized by the scanning electron microscope,and the adhesion and proliferation of cell on the CNFMs were studied by MTT test and the laser scanning confocal microscope.The results showed that the PCL/PEG CNFMs with large pore sizes were more conducive to the growth and proliferation of cell,and were more suitable for tissue engineering.