Electrochemical Time-of-Flight in crosslinked collagen matrix solution: implications of structural changes for drug delivery systems.

Electrochemical Time-of-Flight (ETOF) method was used for the first time to measure the diffusion coefficient of 4-hydroxy-TEMPO, a molecular probe in collagen I matrix solution as a function of its concentration and the extent of crosslinking with glutaraldehyde (GA). The values of the diffusion coefficient were correlated with Circular Dichroism (CD) and viscosity data to assess the changes of the structure of a collagen matrix. The low value of probe diffusion coefficient indicates that the molecular collagen contributes to large diffusion hindrance of the medium.