Fibrin gel-based scaffolds have promising potential for microtia reconstruction. Autologous chondrocytes and chondrocyte cell sheets are frequently used seed cell sources for cartilage tissue engineering. However, the aesthetic outcome of chondrocyte-based microtia reconstruction is still not satisfactory. In this study, we aimed to fabricate the chondrocytes/chondrocyte-microtissues laden fibrin gel auricular scaffold for microtia reconstruction. We designed a unique auricular mold that could fabricate a fibrin gel scaffold resembling human auricle anatomy. Primary chondrocytes were harvested from rabbit auricular cartilage, and chondrocyte cell sheets were developed. Chondrocyte-microtissues were prepared from the cell sheets. The mixture of chondrocytes/chondrocyte-microtissues was laden in fibrin gel during the auricular scaffold fabrication. The protrusions and recessed structure in the auricular scaffold surface were still clearly distinguishable. After a one-week in vitro culture, the 3 D structure and auricular anatomy of the scaffold were retained. And followed by eight-week subcutaneous implantation, cartilaginous tissue was regenerated in the artificial auricular structure as indicated by the results of H&E, Toluidine blue, Safranin O, and type II collagen (immunohistochemistry) staining. Protrusions and depressions of the auricular scaffold were slightly deformed, but the overall auricular anatomy was maintained after 8-week in vivo implantation. Extracellular matrix components content were similar in artificial auricular cartilage and rabbit native auricular cartilage. In conclusion, the mixture of chondrocytes/chondrocyte-microtissues laden fibrin gel auricular scaffold showed a promising potential for cartilaginous tissue regeneration, suggesting this as an effective approach for autologous chondrocyte-based microtia reconstruction.

The purpose of this study was to combine polydioxanone and concentrated growth factor extracts to enhance the stimulation of fibroblast collagen synthesis by polydioxanone in facial plastic. In this experiment, polydioxanone was prepared as a nanoscale bioresorbable scaffold by electrospinning. The PDO-CGF mat was prepared by loading the concentrated growth factor extract onto the polydioxanone mat by lyophilization after soaking. The diameter of the mat fibers was observed by scanning electron microscopy, and the mechanical properties, biocompatibility and cytotoxicity of the material were analyzed. The release rate of transforming growth factor-beat1 (TGF-β1) in the PDO-CGF mat was evaluated by enzyme-linked immunosorbent assay (ELISA), and the amount of collagen synthesis was evaluated by real-time polymerase chain reaction (RT-PCR) and immunofluorescence. The results showed that the PDO-CGF mat had a nanometer-scale fiber diameter and an elastic modulus similar to skin and was able to pull during cell contraction. The PDO-CGF mat showed good biocompatibility, and the appropriate concentration of the PDO-CGF mat can significantly promote cell proliferation. ELISA showed that the PDO-CGF mat stably and continuously released TGF-β1. RT-PCR and immunofluorescence staining showed that the PDO-CGF mat stimulated fibroblasts to synthesize type I and type III collagen. These results indicate that a suitable concentration of the PDO-CGF mat can better promote the synthesis of collagen by fibroblasts.

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