Improved Stability and Cell Response by Intrinsic Cross-Linking of Multilayers from Collagen I and Oxidized Glycosaminoglycans

Abstract

Stability of surface coatings against environmental stress, such as pH, high ionic strength, mechanical forces, and so forth, is crucial for biomedical application of implants. Here, a novel extracellular-matrix-like polyelectrolyte multilayer (PEM) system composed of collagen I (Col I) and oxidized glycosaminoglycans (oGAGs) was stabilized by intrinsic cross-linking due to formation of imine bonds between aldehydes of oxidized chondroitin sulfate (oCS) or hyaluronan (oHA) and amino groups of Col I. It was also found that Col I contributed significantly more to overall mass in CS-Col I than in HA-Col I multilayer systems and fibrillized particularly in the presence of native and oxidized CS. Adhesion and proliferation studies with murine C3H10T1/2 embryonic fibroblasts demonstrated that covalent cross-linking of oGAG with Col I had no adverse effects on cell behavior. By contrast, it was found that cell size and polarization was more pronounced on oGAG-based multilayer systems, which corresponded also to the higher stiffness of cross-linked multilayers as observed by studies with quartz crystal microbalance (QCM). Overall, PEMs prepared from oGAG and Col I give rise to stable PEM constructs due to intrinsic cross-linking that may be useful for making bioactive coatings of implants and tissue engineering scaffolds.

Molecular composition of GAG-collagen I multilayers affects remodeling of terminal layers and osteogenic differentiation of adipose-derived stem cells

“…The presence of Col I fibrils is known to enhance the adhesion of a variety of cells via an ± 2 ² 1 integrin-mediated mechanism [45], which explains also the apparently lower organization of this integrin on HA-based PEMs that contained less Col I. The amount of GAG obviously dominates in the HA-based systems as shown also in our previous work leading formation of smaller of Col I [22], which are poorly recognized by integrins. On the other hand, the increased hydrophilicity of HA-based PEMs may further hinder cell spreading due to the increased water content of the layers coming from the ability of HA to bind large amounts of water [46].…”

“…To enhance their stability, recently an intrinsic crosslinking between aldehydes of oxidized HA or CS and amino groups of Col I was introduced, resulting in enhanced stability and biocompatibility [22]. Here we continue these studies with these multilayer systems looking at the ability of hADSCs to remodel the ECM-like multilayers during culture and the effect of multilayer composition and intrinsic cross-linking on differentiation of hADSCs under the effect of osteogenic growth media.…”

“…While a more comprehensive characterization of the multilayer formation process and also the presence of intrinsic cross-linking were shown in a previous paper [22], here we focused primarily on the characterization of surface properties and layer thickness, which are important for the interaction with cells [34]. Therefore WCA, zeta potential and ellipsometry measurements were performed.…”

“…Among them, layer-by-layer (LbL) technique has emerged as a versatile method, which is based on alternating deposition of biogenic polyelectrolytes such as proteins, polypeptides and GAGs for formation of bioactive multilayer coatings [22,23]. Based on their opposite charge under acidic condition, Col I paired with either hyaluronic acid (HA) or CS represents an interesting system to create multilayers with a composition similar to connective tissue ECM [22].…”

Hydrogels based on collagen and fibrin – frontiers and applications

“…Glycosaminoglycan-modified collagen type I hydrogels are already used in a variety of in vivo and in vitro applications [39]. Oxidized glycosaminoglycans have been investigated by Zhao et al who proved that they have no negative effect on cell behavior [40]. Dialdehyde carboxymethyl cellulose (DCMC) as a crosslinker of collagen improved the thermal stability of collagen and did not interfere with the triple helical structure of the molecules [41].…”