*2.1. Preparation and Characterization of Biphasic Scaffolds from Marine Collagen*

Biphasic, but monolithic scaffolds, composed of biomimetically mineralized salmon collagen [7] and fibrillized jellyfish collagen [9] were successfully obtained by overlaying the two different phases as liquid suspensions, joint freeze-drying and crosslinking. Figure 1 shows the morphology of these scaffolds, both in dry and wet state. Although the stronger swelling of the jellyfish collagen phase is clearly visible, the stability of the whole scaffold is not affected by the different swelling behavior of the phases. This becomes especially obvious, when the microstructure of the scaffolds is analyzed. Interconnecting pores were verified in the transition zone between the two phases (Figure 2). Scanning electron microscopy (SEM) images show the smooth surface of the non-mineralized jellyfish collagen pore walls, as well as the rough morphology of the mineralized salmon collagen, which originates in the presence of hydroxyapatite nanocrystals, decorating the surface (Figure 2).
