| BackgroundCongenital microtia is one of the most common congenital malformations.At present,autologous costal cartilage transplantation is the most commonly used technique in the clinical treatment of this disease.But the complications caused by operations,such as pneumothorax and chest wall malformation,are difficult to completely avoid.In recent years,the development of tissue engineering and regenerative medicine technologies has brought new hope to the treatment of microtia.And the rise of three-dimensional bioprinting technology provides a new method for ear cartilage tissue engineering.Gelatin Methacryloyl(GelMA)is one of the most commonly used biomaterials in the study of three-dimensional bioprinting to construct auricular cartilage.However,as a hydrogel material,GelMA has poor mechanical properties and poor formability.Bacterial nano-cellulose(BNC)is one of the research hot-spots of biomaterials in recent years.It has the characteristics of good biocompatibility and a high Young’s modulus.At present,there are few studies on the application of BNC combined with GelMA in 3D bioprinting to construct auricular cartilage.Therefore,whether the mechanical properties and printability of GelMA can be enhanced by adding BNC and finally building an ideal auricle cartilage needs further research.Objectives1.Explore whether adding BNC can improve the mechanical properties of GelMA/BNC composite hydrogel and find a suitable proportion of composite hydrogel.Select the most appropriate proportion of composite hydrogels and characterize the material properties in vitro.2.Explore the feasibility of composite hydrogel in constructing auricular cartilage scaffolds by 3D bioprinting.Methods1.Add different amounts of BNC to 10%GelMA to make composite hydrogels and use mechanical testing to find the best amount;After selecting the optimal proportion of composite hydrogel,compared with 10%GelMA,the material characterization,printability test,biocompatibility test,and cell migration test were carried out.2.Ear cartilage scaffolds were constructed by 3D bioprinting using composite hydrogel.After being implanted in nude mice of culture in vivo for 4 weeks,8 weeks,12 weeks,and 24 weeks,respectively,the feasibility of the material to construct tissue-engineered cartilage was evaluated by gross morphology,hematoxylin eosin staining(H&E),cartilage special staining(Safranin-O staining,Alcian blue staining),determination of glycosaminoglycan content and total collagen content,and biomechanical tests.Finally,the composite material was used to construct an ear shaped scaffold,and the formation of cartilage tissue was observed in general shape,H&E staining,and special cartilage staining.Results1.The Young’s modulus of the composite hydrogel could be improved by adding an appropriate proportion of BNC to GelMA,and the optimal mass volume ratio of BNC was 0.375%.The composite hydrogel added with BNC had good printability,biocompatibility,and cell migration ability,and it was suitable for 3D bioprinting.2.The cartilage scaffold was successfully printed by 3D bio-printing using composite hydrogel with rabbit ear chondrocytes.The scaffolds were implanted into nude mice for animal experiments.Histological,quantitative,and biomechanical tests showed that the cartilage forming ability and biomechanical properties of the composite hydrogel were better than 10%GelMA.The composite hydrogel was successfully used to construct auricular cartilage scaffold and regenerate auricular cartilage by 3D bioprinting technology.ConclusionsThe composite hydrogel added with an appropriate amount of BNC has better mechanical properties,printability,and biocompatibility than 10%GelMA.And the composite hydrogel has better cartilage forming ability,and the cartilage tissue it makes has better biomechanical properties.This makes it a good choice for 3D bioprinting and and regeneration of ear cartilage. |
PDF Full Text Request