A test method to monitor in vitro storage and degradation effects on a skin substitute

We have investigated a potential test method to monitor changes through possible degradation of a collagen/glycosaminoglycan tissue engineering scaffold in vitro. The method used cyclic voltammetry where the degradation process was measured by determining changes in the apparent diffusion coefficients of thermodynamically reversible couples, ferrocyanide and 1,4-benzoquinone, through the scaffold before and after degradation at low pH and at different temperatures. Scaffold samples were degraded in vitro by exposure to pH 3 for 44 days and also stored in pH 7.4 phosphate saline buffer for one week. Sample temperatures used were 21 °C, 37 °C and 40 °C. The greatest apparent degradation was observed for scaffolds stored at 40 °C. Prior to storage, effective diffusion coefficients were 4.4 × 10−6 cm2 s−1 and 2.6 × 10−10 cm2 s−1 for ferrocyanide and 1,4-benzoquinone, respectively. For these respective compounds values changed to 1.2 × 10−6 cm2 s−1 and 1.0 × 10−6 cm2 s−1 after 37 °C degradation and 2.6 × 10−6 cm2 s−1 and 5.5 × 10−8 cm2 s−1 after pH 3 degradation.