Printing 3D Hydrogel Structures Employing Low-Cost Stereolithography Technology.

Leila Samara S M Magalhães,Fernanda Roberta Marciano,Conceição De Maria Vaz Elias,Gustavo F Sousa,Anderson Oliveira Lobo,Francisco Eroni Paz Santos,Andre S A Furtado,Samson Afewerki

doi:10.3390/jfb11010012

Abstract

Stereolithography technology associated with the employment of photocrosslinkable, biocompatible, and bioactive hydrogels have been widely used. This method enables 3D microfabrication from images created by computer programs and allows researchers to design various complex models for tissue engineering applications. This study presents a simple and fast home-made stereolithography system developed to print layer-by-layer structures. Polyethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA) hydrogels were employed as the photocrosslinkable polymers in various concentrations. Three-dimensional (3D) constructions were obtained by using the stereolithography technique assembled from a commercial projector, which emphasizes the low cost and efficiency of the technique. Lithium phenyl-2,4,6-trimethylbenzoyl phosphonate (LAP) was used as a photoinitiator, and a 404 nm laser source was used to promote the crosslinking. Three-dimensional and vascularized structures with more than 5 layers and resolutions between 42 and 83 µm were printed. The 3D printed complex structures highlight the potential of this low-cost stereolithography technique as a great tool in tissue engineering studies, as an alternative to bioprint miniaturized models, simulate vital and pathological functions, and even for analyzing the actions of drugs in the human body.

Highlights

Both industry and academia have expressed increased interest in the application of various printing technologies [1,2] because they offer great advantages such as faster production, easy access, better quality, cost-effective, tailormade design, minor waste generation, and allow large scale production [3]
gelatin methacryloyl (GelMA) was synthesized according to protocol [24]
Different amounts of each hydrogel were placed on each layer constructed to cover the projection region of the images, and each layer was irradiated with laser light for up to 20 seconds, depending on the light opening and hydrogel composition for initiating the crosslinking processes

Summary

Introduction

Both industry and academia have expressed increased interest in the application of various printing technologies [1,2] because they offer great advantages such as faster production, easy access, better quality, cost-effective, tailormade design, minor waste generation, and allow large scale production [3]. Stereolithography technologies have allowed effective advances in constructing detailed shapes with these hydrogel-based biomaterials made of complex and accurate media with different physical, chemical, and mechanical properties to study, create, and recover lost functional tissues and structures [11,12,13] Challenges such as long manufacturing times and high cost still limit the application of this technology [14]. Polyethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA) have proven to be suitable candidates and have been mostly used to produce printed structures using stereolithography [15] These light-sensitive and photocrosslinkable hydrogels have significant scientific interest due to their great advantages such as biocompatibility, hydrophilicity, and ability to promote various cellular functions, making them suitable for biomedical applications, tissue engineering, and regenerative medicine, pharmaceuticals, and cancer therapies [15,16]. As a proof of concept, a wide range of various designed structures were printed

Materials

Preparation of Formulations for Bioprinting Employing Stereolithography

Stereolithography Setup

Results and Discussions

Mechanical Testing