Quantitative Investigation of the Process Parameters of Electrohydrodynamic Direct-Writing and Their Effects on Fiber Surface Roughness and Cell Adhesion

Chen Jiang,Ben Wang,Kan Wang,Chuck Zhang,Xuzhou Jiang

doi:10.3390/polym12112475

Chen Jiang, Ben Wang + Show 3 more

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https://doi.org/10.3390/polym12112475

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Journal: Polymers	Publication Date: Oct 25, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: Georgia Institute of Technology, Manufacturing Institute

Abstract

Electrohydrodynamic (EHD) direct-writing has been widely used to fabricate micro/nanofibers that can serve as a building block in tissue engineering scaffolds. However, the application of EHD direct-writing in tissue engineering is limited by the lack of fundamental knowledge in the correlations among the process parameters, the fiber surface roughness, and the cell adhesion performance. Without a standardized experimental setting and the quantitative database, inconsistent results have been reported. Here, we quantitatively investigate the process–structure–property relationships as the first step towards a better understanding of the EHD direct-writing technology for tissue engineering. Polycaprolactone (PCL) solution is used as a model ink material, and human mesenchymal stem cells (hMSCs) are used to study cell adhesion on PCL fibers. We investigate the different jetting modes defined by the applied voltage, the feed rate, and the nozzle–collector distance. The quantitative effects of process parameters on the fiber surface roughness and the cell adhesion performance are experimentally determined. The quantitative process–structure–property relationships revealed in this study provide guidelines for controlling the surface roughness and the cell adhesion performance of EHD direct-written fibers. This study will facilitate the application of EHD direct-writing in tissue engineering.

Highlights

Tissue damages caused by diseases or injuries require treatments to facilitate tissue repair, replacement, or regeneration [1]
We demonstrated that the surface roughness of the EHD direct-written fibers, and subsequently, the cell adhesion performance could be precisely tuned by controlling the process parameters of EHD direct-writing
The surface roughness of the EHD direct-written fibers was the largest when the Z reached the lower limit (4 mm in this study), and biological experiments indicated that the larger roughness was beneficial for cell adhesion

Summary

Introduction

Tissue damages caused by diseases or injuries require treatments to facilitate tissue repair, replacement, or regeneration [1]. Organ transplantation remains a major clinical method to repair damaged tissues. The shortage of organ donors necessitates tissue engineering development to develop biological substitutes that restore, maintain, and improve the original functionality of damaged tissues [2,3]. One of the biological substitutes’ key elements is a scaffold that provides a suitable environment for cell adhesion, proliferation, and differentiation [4]. Cell–substrate interactions play a crucial role in deciding the scaffolds’ functionality to regulate cellular activities, ranging from attachment and morphology to proliferation and differentiation through contact guidance. Cell–substrate interactions, relying on a specific binding between the cell membrane’s surface molecules and the substrate, are affected by the physical properties of substrates such as surface roughness, topography, and stiffness [5]. Some of the most commonly used techniques for eliciting the desired cellular responses on biomaterials are photolithography [6] and electron beam lithography [7]

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