Printing 3D Hydrogel Structures Employing Low-Cost Stereolithography Technology

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.

Advances in 3D bioprinting technology for cardiac tissue engineering and regeneration

“…The formulation of cell-laden CLMs suitable for 3D-CTE such as photocrosslinking contributes as a finishing-touch step towards the structural stabilization of the ECM scaffold. In the photo-mediated reaction of photo-manufacturing technology, the photosensitive polymer including the LAP [ 88 ] and RB [ 119 ] can perform cross-linking reactions in situ in the presence of living heart cells and bioactive molecules to greatly promote the rapid prototyping of the printed structure [ 120 ], which can also control the density of the hydrogel networks in real time, mimic biological functions, and release biochemical ligands at a micron-level resolution [ 121 ]. It is through this fixation procedure that 3D-CTE based on hydrogel assistance can be truly fastened into an elaborate bionic shape with topographical characteristics ( Fig.…”

Advances in 3D Printing for Tissue Engineering

“…When a given layer is polymerized, the process is repeated, overlapping the previous layer, up to the moment when the whole scaffold is completed. This method allows the use of the following hydrogel materials (Figure 6) [55]: Polyethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA) [56]; photo-initiators can be also added [57,58]. The adjustment of various polymerization process parameters, including light energy and intensity, speed of printing, layer thickness, and exposure time, enables the achievement of a high-quality (including resolution) product [59][60][61][62][63][64].…”

Current Advances in 3D Bioprinting Technology and Its Applications for Tissue Engineering

“…Compared with the inkjet-based, extrusion-based, and laser-assisted bioprinting techniques, this method uses light to crosslink the bio-inks in the reservoir using a layer-by-layer process. Owing to its working mechanism, this technique is limited to light-responsive bio-inks, typically including gelatin methacrylamide (GelMa) and polyethylene glycol diacrylate (PEGDA) [ 40 ]. In addition to the limitations of options with bio-inks, another main disadvantage of stereolithography is that the reservoir may be filled with photopolymers, which entails material waste and a high cost of experimentation.…”