Proteomics and spectroscopic analyses for the molecular characterization of collagen-based animal glues

Animal glues are widely used in restoration, as adhesives, binders, and consolidants for organic and inorganic materials. Their variable performances are intrinsically linked to the adhesive characteristics of collagen, which determines the chemical, physical, and mechanical properties of the glue. A shotgun proteomic analysis provided animal origin, even when blended, and allowed to distinguish between hide and bone glue on the basis of the presence of collagen type III. Proteomics and analytical pyrolysis coupled to GC-MS have been used to analyse chemical modifications in collagen, demonstrating their variability among different glues and showing that, on average, bone glues are less deamidated than hide glues, but more fragmented, and mixed-collagen glues are overall less deamidated than pure glues. Spectroscopic analyses have also been exploited to gain insights in structural changes occurring upon glue preparation from natural materials.