A novel poly (vinyl alcohol)/poly (ethylene glycol) scaffold for tissue engineering with a unique bimodal open-celled structure fabricated using supercritical fluid foaming

Ping Liu,Ming Tian,Cuihua Liu,Wenhua Chen,Pengju Liu

doi:10.1038/s41598-019-46061-7

Ping Liu, Ming Tian + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-46061-7

Copy DOI

Abstract

In this study, a novel poly (vinyl alcohol) (PVA)/poly (ethylene glycol) (PEG) scaffold was carefully designed via thermal processing and subsequent supercritical fluid (SCF) foaming. Interestingly, a bimodal open-celled structure with interconnected networks was successfully created in the plasticized PVA (WPVA)/PEG scaffold. Large cells were produced from the nucleation sites generated in the PVA phase during rapid depressurization, while plenty of small pores generate in the cell walls of the big cells. The formation mechanism of this cellular structure was studied by considering the various phase morphologies and the diffusion behaviour of the carbon dioxide (CO2) in individual phases. In addition, the intermolecular interactions of the WPVA/PEG blend were studied using X-ray diffraction and FTIR analysis. The results demonstrate that various types of hydrogen bonds among the hydroxyl groups on the PVA chains, PEG and water molecules are formed in the blend system. The realization of thermoplastic foaming of the PVA/PEG blend benefits from the interactions of complexation and plasticization between water and PEG molecules. The SEM images also revealed that L929 fibroblast cells were able to attach and spread on surfaces of the WPVA/PEG samples. Thus the WPVA/PEG scaffold with unique bimodal cellular structure is nontoxic and favours the attachment and proliferation of cells, making it promising for use as the candidate for tissue engineering applications.

Highlights

Environmentally friendly and biodegradable polymer foams have attracted increasing attention from academic and industrial researchers
Over the past few decades, supercritical fluid (SCF) technique has developed into an advantageous method in terms of preparing polymer foams, attributed to its unique features including controllable cellular structure and exemption of toxic organic solvents[8,9]
PEG presents similar polarity and structure to PVA, providing a miscible or partially miscible blend after the melt process. In view of these advantages, PEG can be considered as a good candidate for improving the thermoplastic foaming of neat PVA; the porosity of the PVA scaffold can be controlled by blending various amounts of PEG

Summary

Introduction

Environmentally friendly and biodegradable polymer foams have attracted increasing attention from academic and industrial researchers This is because these porous materials have been widely developed for drug delivery application and as the scaffold for tissue engineering[1,2,3]. PEG presents similar polarity and structure to PVA, providing a miscible or partially miscible blend after the melt process In view of these advantages, PEG can be considered as a good candidate for improving the thermoplastic foaming of neat PVA; the porosity of the PVA scaffold can be controlled by blending various amounts of PEG. The porous PVA/PEG blend scaffold was prepared through thermoplastic foaming using scCO2 as the physical blowing agent. In vitro culture of the L929 fibroblast cells on the WPVA/PEG was performed to evaluate their cell viability with the CCK-8 assay, as it may have potential applications in the field of tissue engineering

Objectives

Methods

Results