Preparation and characterization of keratin and chicken egg white-templated luminescent Au cluster composite film

• We fabricate red-light-emitting keratin & Au cluster films.
• The secondary structure of keratin &Au cluster films show the changes (from random to order structure) of amide I region.
• The blue-shift of absorption peaks in UV–vis spectra indicate the change of protein conformation.
• The TEM images show the size and distribution of Au cluster.
• The LSCM images indicate intensive luminescence of composite films.

The characterization of keratin-chicken egg white-templated luminescent Au cluster composite films were studied using fourier-transform infrared spectroscopy (FTIR) to demonstrate and quantify the secondary transformation of composite films. The results showed that the secondary structure of treated films was transformed from disordered structure to ordered conformation including α-helix conformation and β-pleated-sheet conformation due to the increase of protein-templated luminescent Au cluster. The absorption features of treated films were exhibited by the UV–vis spectra. The bule-shift and decreased intensity indicated the change of microenvironment due to the concentration of protein-templated luminescent Au cluster. The transmission electron microscopy images of composite films supported the aggregation resulting from microenvironment. The effect of protein-templated luminescent Au cluster was characterized by the laser scanning confocal microscope (LSCM) images which showed the gradually intensive luminescence with increasing Au cluster and the transformation from the whiskers to nanoparticle.