Oxygen diffusion through natural extracellular matrices: Implications for estimating "critical thickness" values in tendon tissue engineering

Oxygen is necessary for maintaining cell proliferation and viability and extracellular matrix (ECM) production in 3-dimensional tissue engineering. Typically, diffusion is the primary mode for oxygen transport in vitro; thus, ensuring an adequate oxygen supply is essential. In this study, we determined the oxygen diffusion coefficients of 3 natural ECMs that are being investigated as construct scaffolds for tendon tissue engineering: small-intestine submucosa (SIS), human dermis (Alloderm®), and canine fascia lata. Diffusion coefficients were determined using a standard diffusion cell system. The ranges for each matrix type were: SIS: 7 × 10-6 - 2 × 10 -5 cm2/s, Alloderm®: 1.9 - 3.1 × 10-5 cm2/s, and canine fascia lata: 1.6 - 4 × 10-5 cm2/s. We used the experimental oxygen diffusivity data for these natural ECMs in a mathematical model of oxygen diffusion through a cell-seeded scaffold to estimate the critical size of cell-seeded scaffold that can be cultured in vitro. © Copyright 2008, Mary Ann Liebert, Inc.