Dual-Enzyme Crosslinking and Post-polymerization for Printing of Polysaccharide-Polymer Hydrogel.

Saiji Shen,Qigang Wang,Hongdou Shen,Chu Wu,Ping Chen,Jiayin Shen

doi:10.3389/fchem.2020.00036

Abstract

Polymer hydrogels are ideal bioprinting scaffolds for cell-loading and tissue engineering due to their extracellular-matrix-like structure. However, polymer hydrogels that are easily printed tend to have poor strength and fragile properties. The gradually polymerized reinforcement after hydrogel printing is a good method to solve the contradiction between conveniently printed and high mechanical strength requirement. Here, a new succinct approach has been developed to fabricate the printable composite hydrogels with tunable strength. We employed the HRP@GOx dual enzyme system to initiate the immediate crosslinking of chondroitin sulfate grafted with tyrosine and the gradual polymerization of monomers to form the composite hydrogels. The detailed two-step gelation mechanism was confirmed by the Fluorescence spectroscopy, Electron paramagnetic resonance spectroscopy and Gel permeation chromatography, respectively. The final composite hydrogel combines the merits of enzymatic crosslinking hydrogels and polymerized hydrogels to achieve adjustable mechanical strength and facile printing performance. The dual-enzyme regulated polymer composite hydrogels are the promising bioscaffolds as organoid, implanted materials, and other biomedical applications.

Highlights

IntroductionHydrogels with three-dimensional networks have received wide attention due to their successful applications in tissue engineering (Yue et al, 2015; Mohamad et al, 2018; Qu et al, 2018, 2019; Edri et al, 2019; Feng et al, 2019), biocatalysis (Diaz et al, 2010), biosensor (Wang et al, 2019), cell culture (Lou et al, 2017; Luo et al, 2019), drug delivery (Gao et al, 2018; Xu et al, 2019), biomedicines (Liow et al, 2017), wound healing (Ahmed et al, 2017), and 3D printing (Censi et al, 2011; Pataky et al, 2012; Malda et al, 2013; Li et al, 2015; Loebel et al, 2017; Lin et al, 2019)
Synthesis of Glycidyl methacrylate (GMA)-CS 2.00 g of chondroitin sulfate was added to 50 ml of deionized water, stirred until the chondroitin sulfate was completely dissolved in room temperature, and pH was adjusted to 3.5 with Hydrochloric acid (HCl)
GMA-CS-Ph-OH was oxidized under the catalysis of dual enzyme catalytic system horseradish peroxidase (HRP)@glucose oxidase (GOx) to form α-carbon radicals (Figure 1B)

Summary

Introduction

Hydrogels with three-dimensional networks have received wide attention due to their successful applications in tissue engineering (Yue et al, 2015; Mohamad et al, 2018; Qu et al, 2018, 2019; Edri et al, 2019; Feng et al, 2019), biocatalysis (Diaz et al, 2010), biosensor (Wang et al, 2019), cell culture (Lou et al, 2017; Luo et al, 2019), drug delivery (Gao et al, 2018; Xu et al, 2019), biomedicines (Liow et al, 2017), wound healing (Ahmed et al, 2017), and 3D printing (Censi et al, 2011; Pataky et al, 2012; Malda et al, 2013; Li et al, 2015; Loebel et al, 2017; Lin et al, 2019). Hydrogels formed by natural polysaccharides are suitable for 3D printing and encapsulating biomolecules. They generally have poor elasticity and weak mechanical properties. The covalently bonded crosslinked network (polymeric hydrogel) is elastically deformable, and still maintains strong mechanical properties They generally lack a suitable porous structure to diffuse biomolecules, and it is difficult to obtain a good viscidity window for extruded 3D printing, which are important factors in tissue-repair and 3D

Methods

Results

Conclusion