Blue light activated photodegradation of biomacromolecules by N-doped titanium dioxide in a chitosan hydrogel matrix

•Nitrogen-doped titanium dioxide particles, dispersed in a biocompatible chitosan hydrogel matrix, allows photodegradation under visible light irradiation.•The investigation of the effects of photocatalysis on biomolecules is carried out by a spectroscopic approach overcoming technical issues typical of colloids/proteins mixtures.•Spectroscopic study on the photocatalysis shows significant effects on proteins.