RESUMEN
The preparation of collagen sponges was studied in order to develop tissue engineering scaffolds. Collagen solutions with varying concentrations were obtained by condensing the initial collagen with polyethylene glycol (PEG) at 4 degrees C for different periods of time, and then were freeze-dried to make collagen scaffolds. The porous characteristics of the prepared scaffolds were characterized by use of different methods, including laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and tensile tests. All collagen sponges were shown to have similar interconnected porous structures but were found to have different pore size, porosity, water capacity and the mechanical property, depending on the concentration of collagen solutions. These findings indicate that the way of controlling the concentration of collagen solutions with PEG permits the freeze-drying fabrication of collagen sponges with varying porous features suitable for different tissue engineering purposes.