Spectroscopic study of a KrF excimer laser treated surface of the thin collagen films

The photochemical properties of collagen films before and after KrF excimer laser UV-irradiation with 248 nm were investigated using Raman, FTIR-ATR and fluorescence spectroscopy. It was shown that a single pulse of UV radiation (λ = 248 nm) can affect the conformation and photostability of collagen polypeptide chains. Raman and FTIR-ATR spectra analysis showed that UV laser light is capable of inducing conformational changes in the irradiated collagen films, mainly as a result of breaking of the hydrogen bonds network and losing of water molecules, accounting for the maintaining the structure organisation. Partial decomposition of the main collagen chain is also considered. Fluorescence measurements showed characteristic bands assigned to tyrosine aromatic compound and also to the products of its photochemical degradation given by laser irradiation.The obtained results indicate that the interaction between collagen film and UV laser radiation can be considered as the result of the photomechanical regime, with low thermal degradation, combined with some photochemical transformations.