Gelatine-based bio-nanocomposites

Gelatine is a well-known structural protein widely used in the daily life, as well as in the scientific and technological areas for the preparation of a great variety of composite materials. But in spite of its abundance and common use, gelatine presents itself as a complex biopolymer with a mixed character between a protein, since it is derived from collagen, and a synthetic linear polymer with random spatial arrangement above certain temperature. For numerous applications, mainly in biomedicine, the biocompatible and biodegradable properties of gelatine are crucial, and usually the reinforcement of biopolymer matrix by assembling to inorganic or hybrid nanoparticles is also required to improve its mechanical stability. Alternative treatments such as chemical crosslinking may also contribute to reduce water swelling and enhance the mechanical properties as well as thermal stability. The incorporation of inorganic solids into the proteinous matrix allows tailoring both the mechanical and functional properties of the resulting gelatine-based composites. Many strategies may be followed to tune the functional properties: selection of inorganic solids offering the desired functionalities, grafting of suitable functional groups to the gelatine hybrids, or combination of additional polymers or fillers in ternary composites. In this way, advanced functional materials of increasing complexity are developed from the basis of a very common biopolymer, opening the way for a wide range of applications of the gelatinebased nanocomposites.