Novel gene-activated matrix with embedded chitosan/plasmid DNA nanoparticles encoding PDGF for periodontal tissue engineering

Recently, much attention has been paid to tissue engineering and local gene delivery system in periodontal tissue regeneration. Gene-activated matrix (GAM) blends these two strategies, serving as a local bioreactor with therapeutic gene expression and providing a structural template to fill the lesion defects for cell adhesion, proliferation and synthesis of extracellular matrix (ECM). In this study, we designed a novel GAM with embedded chitosan/plasmid nanoparticles encoding platelet derived growth factor (PDGF) based on porous chitosan/collagen composite scaffold. The chitosan/collagen scaffold acted as three-dimensional carrier and chitosan nanoparticles condensed plasmid DNA. The plasmid DNA entrapped in the scaffolds showed a sustained and steady release over 6 weeks and could be effectively protected by chitosan nanoparticles. MTT assay demonstrated that periodontal ligament cells (PDLCs) cultured into the novel CAM achieved high proliferation. Luciferase reporter gene assay displayed that the novel GAM could express 1.07x10(4) LU/mg protein after 1 week and 8.97x10(3) LU/mg protein after 2 weeks. The histological results confirmed that PDLCs maintained a fibroblast figure and the periodontal connective tissue-like structure formed in the scaffolds after 2 weeks. Semi-quantitative immunohistochemical results suggested that PDGF protein expressed at a relatively high level after 2 weeks. From this study, it can be concluded that the novel GAM had potential in the application of periodontal tissue engineering. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 90A: 564-576, 2009