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Biomolecules and Tissue Properties
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
The triple helix is a right-handed coiled coil and a cooperative quaternary structure stabilized by numerous hydrogen bonds. These chains contain multiple repeats of the amino acid sequence Gly-X-Y, where X and Y are usually proline or hydroxyproline. Of all of the amino acids in the molecule, 33% of them are glycine, and 25% are proline and hydroxyproline. Type I collagen contains 2 αI chains and 1 αII chain. Collagens can be split into two major groups: fiber forming and non-fiber forming. Type I collagen is the most abundant, found in skin, bones, tendons, and ligaments. Type II collagen is the major cartilage collagen, found in cartilage, nucleus pulposus (spine), and vitreous humor (eye). Type III collagen is located in granulation tissue in pliable tissues such as blood vessels, skin (in reticular fiber), uterus, and intestines. Type IV collagen is found in all basement membranes, eye lens, and the kidney. Type V collagen is a minor component in most interstitial tissues and placenta. Type IX collagen is a minor component in hyaline cartilage. Type X collagen is located in mineralizing cartilage, acting as a minor component in hyaline cartilage and ligament. Type XI collagen is found in cartilage, and Type XII collagen is found on the surface of collagen fibrils and may connect fibrillar collagens to other components of the ECM. Collagen I, II, and III are the major types of collagen (responsible for prevention of failure because of tensile and shear forces). Others collagen types are found in small amounts.
Extracellular Matrix–Derived Biomaterials: Molecularly Defined Ingredients and Processing Techniques
Published in Gilson Khang, Handbook of Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine, 2017
H.R. Hoogenkamp, L.R.M. Versteegden, T.H. van Kuppevelt, W.F. Daamen
Collagen is the most abundant protein in man and most other vertebrates. It is a major structural polymer which can be found throughout the body, providing structural integrity and rigidity in tissues like tendons, cartilage, and skin.22 Along with calcium, collagen is important for strength and structure in bones and teeth. So far more than 28 genetically distinct types of collagen have been found, of which type I collagen is most abundant.23 On a cellular level, type I collagen mainly acts as a structural component but it also mediates biological functions like cell binding, migration, growth, and chemotaxis.24 Type II collagen is predominantly found in cartilage, whereas type III collagen can be found in more elastic tissues like the skin. Type IV collagen is a universal component of the basement membrane, a thin sheet of specialized ECM upon which a large number of cell types (epithelium, endothelium, muscle cells) rest and which plays an essential role in cell adhesion. Collagen- based biomaterials have been widely used for tissue engineering applications for a number of reasons, including biocompatibility, biodegradability, low immunogenicity, and low antigenicity.25
Biologic Biomaterials: Tissue-Derived Biomaterials (Collagen)
Published in Joyce Y. Wong, Joseph D. Bronzino, Biomaterials, 2007
To date, 19 proteins can be classified as collagen [Fukai et al., 1994]. Among the various collagens, type I collagen is the most abundant and is the major constituent of bone, skin, ligament, and tendon. Due to the abundance and ready accessibility of these tissues, they have been frequently used as a source for the preparation of collagen. This chapter will not review the details of the structure of the different collagens. The readers are referred to recent reviews for a more in-depth discussion of this subject [Nimni, 1988; van der Rest et al., 1990; Fukai et al., 1994; Brodsky and Ramshaw, 1997]. It is, however, of particular relevance to review some salient structural features of the type I collagen in order to facilitate the subsequent discussions of properties and its relation to biomedical applications.
PVA, licorice, and collagen (PLC) based hybrid bio-nano scaffold for wound healing application
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Md Mehedi Hasan, Md Abdus Shahid
Collagen is naturally occurring proteins and belongs to the class of structural proteins that are long and fibrous and whose roles are distinct from those of globular proteins, such as enzymes. Triple helix 29 collagen variants molecules have been recorded each about 280 nm long marked fibril-forming as type I, II, III, IV, and V. Type I collagen protein is the extracellular matrix in the various connective tissues over 90% of the whole human body protein content. The chemotactic activity of collagen allows it to play a crucial part in every stage of the wound healing process. It promotes cellular migration, which aids in angiogenesis, re-epithelialization, and debridement and promotes the growth of new tissues. As a result, collagen is a common substance utilized to prepare and produce contemporary wound dressings, which are largely meant for chronic wounds. For the purpose of applying wound dressings, a study developed electrospun collagen/PCL/zein hybrid nanofibers that were also infused with aloe vera and zinc oxide nanoparticles (ZnO NPs). This suggests a synergistic impact of dual drug-loaded nanofibers [33].
Bioinks—materials used in printing cells in designed 3D forms
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Dilara Goksu Tamay, Nesrin Hasirci
Collagen is one of the most common proteins that exist in mammals. Since it is the most abundant protein in the body and is the main component of the articular cartilage and meniscus ECM, it has excellent biocompatibility. Collagen promotes cell adhesion and regeneration [68]. Its structure is fibrous with good viscoelastic properties, and it enhances the mechanical stability of tissues such as bone and skin. Chemical structure of collagen contains mostly Glycine (Gly), Proline (Pro), Hydroxyproline (Hyp) and any other aromatic and sulfur-containing amino acid (X) [69]. Therefore, the characteristic structure is shown as Gly-Pro-X. Collagen molecule is in a triple helix form, named tropocollagen. It has three polypeptide chains (each has the conformation of a left handed helix) wrapped around each other forming a supramolecular quaternary structure as right handed triple helix conformation. When the tropocollagens come together, they form larger collagen fibrils, and when fibrils aggregate, they form collagen fibers with a well-ordered organization as crystals. There are more than 28 different types of collagen. Types I, II, III, and V are the main ones that make up the essential part of collagen in bone, cartilage, tendon, skin, and muscle. In bone structure, more than 90% is type I collagen [68,69]. Therefore, most of the collagen hydrogels are produced from type I collagen.
Medical textiles
Published in Textile Progress, 2020
Collagen fibres are natural macromolecular protein assemblies that play a vital role in structures that support tensile mechanical loads in the human body/animal bodies. There are different subtypes of collagen but the most abundant form is type I collagen, the primary structural motif in tendon and ligament [90]. The structure of collagen is complex; right-handed triple helical structures are assembled into microfibres by hydrogen bonds. Cross-linking aggregates the chains into a triple helix to provide stability to the molecule and then several molecules aggregate in a quarter-staggered array to form microfibrils, which further aggregate to form the fibres [91, 92]. Collagen can be extracted from connective tissues, purified and reconstituted into gels and scaffolds. Purified collagen remains a preferred base for ligament and tendon tissue engineering due to its low antigenicity, a chemotactic surface structure for fibroblasts, biocompatibility and proteolytic degradation pathways; collagen-based fibres are in contemporary clinical use as sutures, though these cannot be used for scaffolding due to inflammatory tissue reactions [93].