The effect of liquid platelet-rich fibrin on oral cells and tissue engineered oral mucosa models in vitro

Liquid formulations of platelet-rich fibrin (Liquid-PRF) have been shown to promote oral soft tissue healing for some clinical applications, however, the efficacy of liquid-PRF as a standalone treatment remains uncertain. The aim of the present study was to investigate the effects of liquid-PRF on oral cells in vitro using two-dimensional cell culture and three-dimensional tissue-engineered oral mucosa models. Media was conditioned with liquid-PRF prepared from blood samples and applied to oral fibroblasts, keratinocytes and tissue-engineered oral mucosa models. Metabolic activity, migration, proliferation and epithelial morphology were assessed. Liquid-PRF was shown to be biocompatible, with no cytotoxic effects observed on oral mucosa cells or 3D oral mucosa models. Cytokine analysis confirmed the presence of key growth factors, including PDGF-BB, TGF-β1, and EGF. Liquid-PRF increased oral fibroblast proliferation and promoted keratinocyte migration in 2D cultures. In tissue-engineered oral mucosa models, liquid-PRF showed no significant improvement in metabolic activity, epithelium thickness, morphology or proliferative capacity. The results suggest that growth factors in liquid-PRF were able to stimulate the proliferation and migration of oral mucosa cells in 2D culture, however these effects could not be demonstrated in 3D oral mucosa models. Factors secreted from liquid PRF were able to support the growth of cells and the development and maintenance of a healthy epithelium. Despite improvements in keratinocyte migration and fibroblast proliferation the results from 3D models indicate that factors secreted from liquid-PRF alone may not be sufficient to stimulate oral soft tissue repair.