Collagen-based matrices with axially oriented pores.

The aim of this work was the implementation of a simple technique for the production of cylindrical collagen-based scaffolds with axially oriented pore channels. Matrices with this particular porous structure have the potential to improve the regeneration of peripheral nerves and spinal cord by physically supporting and guiding the growth of neural structures across the site of injury. The regenerative potential may be further enhanced when the collagen scaffold is used as a delivery vehicle for exogenous cells and growth factors. The scaffold manufacturing technique described here is based on unidirectional freezing of a collagen suspension and subsequent freeze-drying, which produces nearly axially oriented pores. The mean pore size is dependent on both the concentration of collagen in suspension and the temperature of freezing. Environmental scanning electron microscopy and light microscopy were used to assess qualitatively and quantitatively the pore size and the pore orientation. In particular the definition of an orientation index (OI) was employed as a means to quantify the orientation of the pore channels inside the scaffolds.