Wet-spinnability and crosslinked fibre properties of two collagen polypeptides with varied molecular weight

TL;DR

This study explores how molecular weight influences the wet-spinning and crosslinking properties of collagen-derived fibres, demonstrating the impact on fibre morphology, mechanical stability, and degradation in physiological environments.

Contribution

It introduces a comparative analysis of wet-spun collagen polypeptides with different molecular weights, highlighting effects on fibre formation and mechanical properties under various conditions.

Findings

Fibre morphology varies significantly with molecular weight and spinning conditions.

Covalent crosslinking enhances tensile modulus and stability of fibres.

Fibres degrade nearly completely after 5 days in physiological conditions.

Abstract

The formation of naturally-derived materials with wet stable fibrous architectures is paramount in order to mimic the features of tissues at the molecular and microscopic scale. Here, we investigated the formation of wet-spun fibres based on collagen-derived polypeptides with comparable chemical composition and varied molecular weight. Gelatin and hydrolysed fish collagen (HFC) were selected as widely-available linear amino-acidic chains of high and low molecular weight, respectively, and functionalised in the wet-spun fibre state in order to preserve the material geometry in physiological conditions. Wet-spun fibre diameter and morphology were dramatically affected depending on the polypeptide molecular weight, wet-spinning solvent (i.e. 2,2,2-Trifluoroethanol and dimethyl sulfoxide) and coagulating medium (i.e. acetone and ethanol), resulting in either bulky or porous internal geometry. Dry-state tensile moduli were significantly enhanced in gelatin and HFC samples following covalent crosslinking with activated 1,3 phenylenediacetic acid (Ph) (E: 726 +/- 43 - 844 +/- 85 MPa), compared to samples crosslinked via intramolecular carbodiimide-mediated condensation reaction (E: 588 +/- 38 MPa). Resulting fibres displayed a dry diameter in the range of 238 +/- 18 - 355 +/- 28 micron and proved to be mechanically-stable (E: 230 kPa) following equilibration with PBS, whilst a nearly-complete degradation was observed after 5-day incubation in physiological conditions.