Collagen and Its Modifications-Crucial Aspects with Concern to Its Processing and Analysis

Abstract

Many connective tissue diseases and defects are associated with poor synthesis or excessive degradation of collagen. The modern tissue engineering approach is to replace the defective site via the implantation of a biocompatible scaffold which serves as a carrier for cell incorporation, proliferation, and growth. Collagen is widely used in the field of clinical medicine in connection with both hard and soft tissue applications. However, certain collagen properties such as poor dimensional stability, poor in vivo mechanical strength, low degree of elasticity, variable nature in terms of enzymatic degradation, crosslinking density, fiber size, trace impurities, and side effects frequently limit both its analysis and application. This review focuses particularly on the processing and modification of collagen type I with respect to its biological and mechanical properties. The processing of collagen into scaffolds is crucial to mimic successfully the extracellular matrices. Moreover, the review suggests several ways in which the most common problems related to the isolation, handling, electrospinning, and crosslinking of collagen can be overcome while maintaining its native character as much as possible. Further, the review provides a summary of the analytical methods available for the physicochemical characterization of collagen with respect to both its molecular and submolecular structure.

Rheological Properties of Coordinated Physical Gelation and Chemical Crosslinking in Gelatin Methacryloyl (GelMA) Hydrogels

“…Modification of collagen is primarily limited by availability of accessible functional groups, e.g., free amines, thus requiring more complex modification strategies to generate the desired macromers. [ 11–14 ] Collagen exhibits thermal gelation reversibility, limited mechanical strength, batch‐to‐batch variability, and high cost. To address these disadvantages, collagen triple helices can be denatured or chemically modified.…”

Physicochemical Characterization of Bilayer Hybrid Nanocellulose-Collagen as a Potential Wound Dressing

“…The other advantage of ovine-based CECM dressing is that it can shield itself from noxious matrix metallopeptidase (MMP) activity present in the chronic wound microenvironment cushioned by its broad-spectrum buffering capacity for proteolytic collagenases and gelatinase [ 13 ]. Nevertheless, the downsides of collagen are mainly poor structural stability and mechanical properties [ 14 , 15 ]. An alternative of cross-linking the collagen may improve the tensile strength, and incorporation of additional biomaterial to form hybrid or composite ovine-based collagen dressing may further impart its mechanical characteristics.…”

A New Approach for Glyco-Functionalization of Collagen-Based Biomaterials

“…These include a) the interactions with other ECM proteins and soluble proteins (interactors), b) the interaction with cell surface receptors, and c) post-translational modifications (i.e, in collagen type I, the O -glycosylation at the hydroxylysine residues). Data reported in the literature on collagen triple helix formation [18] suggests that the glycosylation of collagen chains has an important contribution to surface roughness variations in cell–ECM and ECM–ECM interaction [19,20]. As verified by AFM analysis, morphological changes in neoglycosylated collagen could have an influence on both the inter-molecular and inter-fibrillar interactions of the triple-helical domain of collagen films, contributing also to the improved biological activity of the produced films.…”