| Objective:A polyvinyl alcohol(PVA)/aramid nanofibers(ANFs)hydrogel scaffold was prepared by 3D printing technology,and its internal structure,physicochemical properties,mechanical properties(tensile,compression,friction)and biological properties(cell proliferation ability and AO/EB staining)were investigated.This study provides some feasibility and theoretical basis for the application of PVA/ANFs in cartilage tissue engineering.Methods:(1)Prepare ANFs solution(3 mg/mL)and PVA solution(20 wt.%),20 mL of PVA solution and 0,1,2,3,4 mL of ANFs solution were homogeneously mixed to obtain five different concentrations of ink,named as PVA,A1,A2,A3,A4.The rheological properties were tested to evaluate the printable performance.(2)Five PVA/ANFs hydrogel scaffolds with different concentrations of ANFs were prepared by 3D printing technology,and F127 was used as support during the printing process,and the scaffold hydrogel was cross-linked by freeze-thaw cycles after the printing was completed.Then,Surface morphology and internal structure of ANFs and PVA/ANFs observed by transmission electron microscopy(TEM),scanning electron microscopy(SEM)and Fourier infrared spectroscopy(FT-IR).(3)The mechanical properties(tensile,compression,friction),initial water content,swelling rate and degradation rate of each group of scaffolds were tested and evaluated.(4)The effect of each group of scaffold materials on the survival rate and value-added rate of chondrocytes was evaluated by MTT method and AO/EB staining method.Results:(1)Rheological tests confirmed that the five hydrogels have certain printable properties.(2)FT-IR test results showed that PVA was cross-linked with ANFs and between PVA and PVA by hydrogen bonding;SEM and TEM observed that the surface of ANFs was smooth and uniformly dispersed;SEM showed that the surface of PVA hydrogel scaffold showed a dense structure,while the group with the introduction of ANFs showed a porous double network structure,and the shuttle of ANFs was visible inside it.(3)The mechanical test results showed that the mechanical properties of each group of hydrogel scaffolds improved after the introduction of ANFs compared with the pure PVA group,and the maximum tensile strength and elongation of the best A3 group could reach 3.47 MPa and 793%,respectively.The results of compression performance tests showed that all groups of scaffolds had good compression resistance and could recover to their initial height after 10 cycles of compression to50% of their initial height.The results of the swelling rate test showed that the initial water content of the hydrogel scaffolds in each group was above 80%,similar to that of natural cartilage tissue,and had a certain degradation rate.The tribological test results showed that the tribological coefficient of pure PVA fluctuated around 0.5 m.Compared with the PVA group,the other four groups showed a significant trend of lower tribological coefficient after the introduction of ANFs.This indicates that the PVA/ANFs hydrogel scaffold has good lubricity to reduce damage to articular cartilage during motion,as well as a good coefficient of friction for obtaining good fixation at the target location in case of cartilage defects.(4)Biological test results showed that the cell survival rate of hydrogel scaffolds in each group was higher than 90% throughout the co-culture period,and the cell survival rate in some groups was more than 100%,which indicated that the hydrogel material was not only non-cytotoxic but even able to promote cell growth,and we further verified the conclusion by Calcein-AM/PI double staining method.Conclusions:The experimental results showed that the tensile strength and elongation of PVA hydrogels were significantly improved due to the formation of multiple hydrogen bonds between PVA and ANFs.Moreover,the PVA/ANFs scaffold has similar water content and swelling rate as natural cartilage,as well as good biocompatibility and lubricity properties.It is an ideal material for application in cartilage tissue engineering. |
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