Collagenous Bioadhesives

Abstract

Collagen-based bioadhesives, also known as animal glues, are derived from animal parts (e.g. skin, bone, and cartilage). They have been widely used in the production of decorative wood working, paintings, bookbinding, and other historical objects for centuries as well as for their restoration and preservation [1].

Collagen, in which the term (kólla) is derived from the Greek word for glue, is a fibrous structural protein with a hierarchical microstructure at different length scales. Collagen is water insoluble and can be turned into water-soluble gelatine through the denaturation process. Upon denaturation, the triple helix structure in collagen unwinds and turns into random coils giving gelatinous animal glue. Gelatinous animal glue can be dissolved in water and during gelling and subsequent drying, the random protein coils undergo partial renaturation back into triple helices. These triple helices in the adhesive act as physical cross-links leading to a continuous three-dimensional network structure [2]. These microstructural features affect the physical and mechanical performance of the glue at micro and macro scales.

In this study four different adhesives from different animal species both mammalian and fish are investigated. These adhesives are bovine bone, bovine skin, rabbit skin, and fish. For this study, thin films of these adhesives were manufactured using the solution casting method. Physical and mechanical behaviour of the adhesives were characterized using Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), Bloom strength evaluation, and uniaxial tensile tests.