3D Printing of Silk Particle-Reinforced Chitosan Hydrogel Structures and Their Properties

Abstract

Hydrogel bioprinting is a major area of focus in the field of tissue engineering. However, 3D printed hydrogel scaffolds often suffer from low printing accuracy and poor mechanical properties because of their soft nature and tendency to shrink. This makes it challenging to process them into structural materials. In this study, natural chitosan hydrogel scaffolds were, for the first time, reinforced with milled silk particles and fabricated by 3D printing. Compared with pure chitosan scaffolds, the addition of silk particles resulted in up to a 5-fold increase in compressive modulus as well as significantly better printing accuracy and improved scaffold stability. The chitosan/silk inks flowed well during printing; loading of up to 300% silk (w/w) resulted in only minor changes in the rheological properties of the ink. Particle loading also enabled tuning of the surface roughness of the scaffolds and improved scaffolds’ biodegradability. The printed composite hydrogel scaffolds showed no cytotoxicity and supported adherence and growth of human fibroblast cells.

Hydrogels for Bioprinting: A Systematic Review of Hydrogels Synthesis, Bioprinting Parameters, and Bioprinted Structures Behavior

“…For this reason, to solve these poor mechanical properties it is usually combined with other materials as hyaluronic acid (Kim et al, 2019 ), alginate/collagen (Aydogdu et al, 2019 ), collagen/agarose (Campos et al, 2015 ), and alginate/gelatin/collagen (Akkineni et al, 2016 ). Chitosan also appears combined with silk (Zhang J. et al, 2018 ) and modified with hydroxybutil groups to improve its water solubility or with oxidized chondroitin sulfate to improve its mechanical properties (Li et al, 2019 ).…”

3D Printing and Bioprinting Nerve Conduits for Neural Tissue Engineering

“…Due to its softness, silk fibroin is seldom used to prepare 3D printing scaffolds alone, and it is more often combined with other materials to obtain scaffolds with stronger performance. Zhang et al [85] printed the chitosan hydrogel scaffold with silk fibroin particles incorporated. Compared with the pure chitosan scaffold, adding silk fibroin led to 5-fold enhanced compressive modulus and improved printing accuracy and stability.…”

Glycerylphytate as an ionic crosslinker for 3D printing of multi-layered scaffolds with improved shape fidelity and biological features

“…This methodology allowed fast printing without using supporting templates 21,36,[41][42][43][44][45] or neutralization and washing steps. 5,7,24,28,30,46 The as-printed scaffolds were ready to be used for biological tests.…”