Characteristics of Reconstituted Collagen Fibers from Chicken Keel Cartilage Depends on Salt Type for Removal of Proteoglycans

Anna Pudło,Wiesław Kopeć,Szymon Juchniewicz

doi:10.3390/molecules26123538

Anna Pudło, Wiesław Kopeć + Show 1 more

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https://doi.org/10.3390/molecules26123538

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Abstract

The aim of the presented research was to obtain reconstituted atelocollagen fibers after extraction from poultry cartilage using the pepsin-acidic method in order to remove telopeptides from the tropocollagen. Firstly, we examined the extraction of collagen from the cartilage extracellular matrix (ECM) after proteoglycans (PG) had been removed by the action of salts, i.e., NaCl or chaotropic MgCl2. Additionally, the effects of the salt type used for PG and hyaluronic acid removal on the properties of self-assembled fibers in solutions at pH 7.4 and freeze-dried matrices were investigated. The basic features of the obtained fibers were characterized, including thermal properties using scanning calorimetry, rheological properties using dynamic oscillatory rheometry, and the structure by scanning electron microscopy. The fibers obtained after PG removal with both analyzed types of salts had similar thermal denaturation characteristics. However, the fibers after PG removal with NaCl, in contrast to those obtained after MgCl2 treatment, showed different rheological properties during gelatinization and smaller diameter size. Moreover, the degree of fibrillogenesis of collagens after NaCl treatment was complete compared to that with MgCl2, which was only partial (70%). The structures of fibers after lyophilization were fundamentally different. The matrices obtained after NaCl pretreatment form regular scaffolds in contrast to the thin, surface structures of the cartilage matrix after proteoglycans removal using MgCl2.

Highlights

IntroductionReconstituted collagen fibers (self-assembled after increasing the ionic strength or pH in monomer solutions) is the basis for creating matrices and scaffolding of biomaterials replacing soft or hard tissues, e.g., bones [1,2,3,4,5]
Reconstituted collagen fibers is the basis for creating matrices and scaffolding of biomaterials replacing soft or hard tissues, e.g., bones [1,2,3,4,5]
The removal of proteoglycans from cartilage with MgCl2 with strong chaotropic properties reduces the potential ability of atelocollagen self-assembly in solutions (70% of the total amount of atelocollagen), and the resulting collagen fibers are thicker than those obtained from cartilage after PG removal with NaCl

Summary

Introduction

Reconstituted collagen fibers (self-assembled after increasing the ionic strength or pH in monomer solutions) is the basis for creating matrices and scaffolding of biomaterials replacing soft or hard tissues, e.g., bones [1,2,3,4,5]. The main materials used for this purpose are reconstituted fibers of type I collagen obtained by the acid method or acid-enzymatic method with pepsin [6]. The latter is considered the most advantageous, as it removes telopeptides (the so-called atelocollagen is formed), which reduces the immunogenicity of the obtained biomaterials that can be introduced into human tissues [7,8,9]. The second method provides cleaner collagen and facilitates the use of valuable proteoglycan fraction (mainly glycosaminoglycan chondroitin sulfate) for dietary supplements or the bioengineering of matrix components [2,6]

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