Porous Poly(2-hydroxyethyl methacrylate) Hydrogel Scaffolds for Tissue Engineering: Influence of Crosslinking Systems and Silk Sericin Concentration on Scaffold Properties

Nantaprapa Tuancharoensri; Sukhonthamat Sonjan; Sudarat Promkrainit; Jinjutha Daengmankhong; Preeyawass Phimnuan; Sararat Mahasaranon; Jirapas Jongjitwimol; Pensri Charoensit; Gareth M Ross; Céline Viennet; Jarupa Viyoch; Sukunya Ross

doi:10.3390/polym15204052

Porous Poly(2-hydroxyethyl methacrylate) Hydrogel Scaffolds for Tissue Engineering: Influence of Crosslinking Systems and Silk Sericin Concentration on Scaffold Properties

Polymers (Basel). 2023 Oct 11;15(20):4052. doi: 10.3390/polym15204052.

Authors

Affiliations

¹ Biopolymer Group, Department of Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
² Department of Pharmaceutical Technology, Center of Excellence for Innovation in Chemistry, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
³ Center of Excellence in Biomaterials, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
⁴ Biomedical Sciences Program, Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok 65000, Thailand.
⁵ UMR 1098 RIGHT INSERM EFS FC, DImaCell Imaging Resource Center, University of Franche-Comté, 25000 Besançon, France.

Abstract

Tailored porous structures of poly(2-hydroxyethyl methacrylate) (PHEMA) and silk sericin (SS) were used to create porous hydrogel scaffolds using two distinct crosslinking systems. These structures were designed to closely mimic the porous nature of the native extracellular matrix. Conventional free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) was performed in the presence of different concentrations of SS (1.25, 2.50, 5.00% w/v) with two crosslinking systems. A chemical crosslinking system with N'N-methylene bisacrylamide (MBAAm) and a physical crosslinking system with dimethylurea (DMU) were used: C-PHEMA/SS (crosslinked using MBAAm) and C-PHEMA/pC-SS (crosslinked using MBAAm and DMU). The focus of this study was on investigating the impact of these crosslinking methods on various properties of the scaffolds, including pore size, pore characteristics, polymerization time, morphology, molecular interaction, in vitro degradation, thermal properties, and in vitro cytotoxicity. The various crosslinked networks were found to appreciably influence the properties of the scaffolds, especially the pore sizes, in which smaller sizes and higher numbers of pores with high regularity were seen in C-PHEMA/1.25 pC-SS (17 ± 2 μm) than in C-PHEMA/1.25 SS (34 ± 3 μm). Semi-interpenetrating networks were created by crosslinking PHEMA-MBAAm-PHEMA while incorporating free protein molecules of SS within the networks. The additional crosslinking step involving DMU occurred through hydrogen bonding of the -C=O and -N-H groups with the SS, resulting in the simultaneous incorporation of DMU and SS within the PHEMA networks. As a consequence of this process, the scaffold C-PHEMA/pC-SS exhibited smaller pore sizes compared to scaffolds without DMU crosslinking. Moreover, the incorporation of higher loadings of SS led to even smaller pore sizes. Additionally, the gelation time of C-PHEMA/pC-SS was delayed due to the presence of DMU in the crosslinking system. Both porous hydrogel scaffolds, C-PHEMA/pC-SS and PHEMA, were found to be non-cytotoxic to the normal human skin dermal fibroblast cell line (NHDF cells). This promising result indicates that these hydrogel scaffolds have potential for use in tissue engineering applications.

Keywords: crosslinking; poly(2-hydroxyethyl methacrylate); porous scaffolds; silk sericin.

Grants and funding

This research received no external funding.