Platelet-rich plasma (PRP) has mixed growth factors such as TGF-ß1 and TGF-ß2, vascular epithelial growth factor (VEGF), platelet-derived growth factor (PDGF), and insulin-like growth factor (IGF). These growth factors appear to play an important role in wound healing and are assumed as promoters of tissue regeneration. Moreover, PRP was used as injectable scaffold seeded with chondrocytes to regenerate cartilage. In their previous study, the investigators concluded that growth factors in PRP can effectively react as a growth factor cocktail to induce human nucleus pulposus proliferation and differentiation, and also promote tissue-engineered nucleus pulposus formation. The investigators also have a hypothesis that PRP can promote tissue-engineered microtia auricular cartilage formation. TGF- ß1 exists in the highest concentration and is more important among all of the growth factors released from PRP. So TGF- ß1 can be used as the core ingredient and the indicator for applying PRP in these studies. The aim of this study was to compare the histological and biochemical character of microtia chondrocytes treated with and without PRP.