# Formulation and 3D Printing of Collagen/Chitosan Inks: Tailoring the Scaffold Properties

## TL;DR

Researchers developed a collagen/chitosan ink for 3D printing that supports cartilage tissue growth and maintains structural stability.

## Contribution

A novel 80:20 collagen/chitosan hydrogel formulation was developed with optimal printability and biological performance for cartilage engineering.

## Key findings

- The 80:20 collagen/chitosan ink showed shear-thinning behavior and dimensional stability suitable for 3D printing.
- The scaffolds supported cell adhesion, proliferation, and extracellular matrix production by chondrocytes and stem cells.
- Sustained sulfated glycosaminoglycan deposition was observed over 28 days, indicating effective matrix formation.

## Abstract

The development of inks with suitable rheological, physicochemical, mechanical, and biological properties is crucial for the successful fabrication of functional scaffolds via extrusion-based 3D printing. In this study, collagen/chitosan hydrogels with varying polymer ratios were developed and characterized to evaluate their printability and suitability for cartilage tissue engineering. Rheological analyses revealed that all samples exhibited shear-thinning behavior and solid-like viscoelasticity, with the formulation of an 80:20 COL/CHI ratio (20CHI) demonstrating optimal filament formation and dimensional stability. Physicochemical analyses confirmed the preservation of the collagen triple helix and the formation of hydrogen bonding between chitosan and collagen. 20CHI scaffolds showed swelling capacity and high cohesiveness. In vitro studies confirmed the cytocompatibility of the scaffolds with murine fibroblasts and the ability of the scaffolds to promote adhesion, proliferation, and extracellular matrix production of both chondrocytes and adipogenic mesenchymal stem cells (aMSCs). Quantification of sulfated glycosaminoglycan (sGAG) indicated sustained matrix deposition over 28 days, particularly by chondrocytes. These findings demonstrate that 20CHI hydrogel is a promising candidate for 3D printing of biomimetic scaffolds for cartilage regeneration.