Effects of Temperature on the FT NIR Raman Spectra of Fish Skin Collagen

The development of regenerative medicine turns attention toward native collagen as a biocompatible material. Particularly interesting is fish skin collagen, which is relatively easy to extract comparing mammalian tissues and free of some pathogens that are dangerous to humans. The paper presents results of IR Raman spectroscopy studies of silver carp (Hypophthalmichthys molitrix) skin collagen. As collagen properties result from its structure and conformation, both sensitive to temperature, FT NIR Raman spectroscopy is an excellent tool to characterize the molecular structure of fish skin collagen, particularly in temperature range typical for the manufacturing processes of biomedical products. Therefore, the Raman spectra were recorded in a temperature range of 300 to 403 K. The analysis of Raman spectra of prepared collagen films, particularly in the range of the bands related to amide I and amide III entities, showed a high content of alpha-helix and alpha-helix type molecular organization in fish skin collagen. Additionally, the secondary structure of the studied fish skin collagen is stable up to similar to 358 K. Heating to 403 K leads to irreversible changes in the molecular structure of fish skin collagen. It was found that the Raman spectrum of fish skin collagen preheated in this manner becomes similar to the spectrum of the collagen obtained from bovine Achilles tendon, whose secondary structure does not change up to 403 K.