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 properties of collagen, which determine the chemical, physical, and mechanical properties of the glue. We have molecularly characterized the protein components of a range of homemade and commercial glues using mass spectrometry techniques. A shotgun proteomic analysis provided animal origin, even when blended, and allowed us to distinguish between hide and bone glue on the basis of the presence of collagen type III, which is abundant in connective skin/leather tissues and poorly synthetized in bones. Furthermore, chemical modifications, a consequence of the preparation protocols from the original animal tissue, were thoroughly evaluated. Deamidation, methionine oxidation, and backbone cleavage have been analyzed as major collagen modifications, 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. We believe that these data may be of general analytical interest in the characterization of collagen-based materials and may help restorers in the selection of the most appropriate materials to be used in conservation treatments.

Fungi produce surface-active proteins, among which hydrophobins are the most characterized and attractive also for their ability to form functional amyloids. Our most recent findings show that these abilities are shared with other classes of fungal proteins. Indeed, in this paper, we compared the characteristics of a class I hydrophobin (Vmh2 from Pleurotus ostreatus) and an unknown protein (named PAC3), extracted from the marine fungal strain Acremonium sclerotigenum, which does not belong to the same protein family based on its sequence features. They both proved to be good biosurfactants, stabilizing emulsions in several conditions (concentration, pH, and salinity) and decreasing surface tension to a comparable value to that of some synthetic surfactants. After that, we observed for both Vmh2 and PAC3 the formation of giant fibers without the need for harsh conditions or long incubation time, a remarkable ability herein reported for the first time.

The main aim of this work is to account for the prevention and control of microbial growth on surfaces of interest in medical technology. Surface modification is often achieved by physiotherapy or chemical treatments that can involve time-consuming steps, hazardous reagents, and harsh conditions. One of the ways to overcome these drawbacks is the use of surface-active proteins such as hydrophobins. They can form stable protein layers on different surfaces, serving as anchoring points for other molecules of interest. The fungal hydrophobin Vmh2, already exploited for its adhesive ability, has been fused with the antimicrobial peptide GKY20, forming the chimeric protein used herein for functionalizing polystyrene (PS) and bacterial cellulose (BC). As a natural biomass, BC has multiple advantages, including biodegradability, low cost, renewability, high purity, and excellent mechanical properties. The chimeric protein has been proven to successfully adhere to both surfaces. A strong decrease in biofilm formation on PS and a good bactericidal effect of BC have been demonstrated. These findings provide evidence of an alternative strategy to obtain functional composites using a green, easy process.