Читать книгу Biomolecules from Natural Sources - Группа авторов - Страница 60

Collagen and gelatine are animal polymers found in skin and connective tissues. Collagen degraded to high molecular weight polypeptide, called gelatine, can be obtained by thermal denaturing of collagen. Gelatin is a water-soluble proteinaceous substance [130]. Gelatin is an important high molecular weight polypeptide hydrocolloid. It is commonly used in a wide range of food, medicinal, pharmaceutical, and polymeric materials. Most hydrocolloids are polysaccharide, whereas gelatin is a protein containing all the amino acids except tryptophan [131]. It was fabricated to different forms to match different applications [132]. It is essential in drug caps, X-rays, photographic film development and food processing. Gelatin grades used in drug delivery and tissue engineering are also available in a wide range of viscosities. It does not show antigenity and is resorbable in vivo. Its physico-chemical properties can be suitably modulated. Gelatine can be plasticized thanks to the addition of water or of glycerol. There is, however, a limit to the use of this interesting material because there is a risk of viral animal contamination. Blends of polyvinyl alcohol and gelatine are the object of studies and research. Elastin, albumine and fibrin are other proteins from animal sources. They have been investigated especially for various biomedical applications. Elastin is used as a biopolymer in enhancing cellular uptake in the tumor cells [82, 83, 133–136].