In Vitro Cartilage Tissue Engineering Using Porous Collagen/PLLA Nanoparticle Hybrid Scaffold

Porous collagen/poly L-lactic acid (PLLA) nanoparticle hybrid scaffolds were evaluated for application in the construction of engineered cartilage in terms of biocompatibility and bioactivity. The hybrid scaffolds were prepared by mixing various amounts of surface-modified PLLA nanoparticles with collagen solution, freeze drying, and cross-linking. PLLA nanoparticles that were homogeneously distributed in the collagen matrix effectively improved the mechanical properties of the scaffold without significantly influencing the microstructure, and slowed down degradation. In vitro cell seeding and culture studies showed that cells infiltrated into the scaffolds and dispersed homogeneously. The proliferation of cells in the hybrid scaffold increased with increasing number of PLLA nanoparticles. In addition, strengthening the scaffolds with PLLA nanoparticles helped to resist the shrinkage of the engineered tissue during in vitro culture. The glycosaminoglycan (GAG) content in the hybrid scaffolds also increased with the addition of PLLA nanoparticles. hematoxylin-eo sin (HE), toluidine blue, and immunohistochemical staining and reverse transcription polymerase chain reaction (RT-PCR) analysis of the chondrocyte/scaffold constructions indicated that the hybrid scaffold promoted the formation of cartilage tissue, resulting in engineered cartilage with a higher compressive modulus compared with that of cartilage cultured on a pure collagen scaffold. These results demonstrate that a porous collagen/PLLA nanoparticle hybrid scaffold is biocompatible, making it suitable for cartilage tissue engineering.