Application of visible light-based projection stereolithography for live cell-scaffold fabrication with designed architecture

Abstract

One-step scaffold fabrication with live cell incorporation is a highly desirable technology for tissue engineering and regeneration. Projection stereolithography (PSL) represents a promising method owing to its fine resolution, high fabrication speed and computer-aided design (CAD) capabilities. However, the majority of current protocols utilize water-insoluble photoinitiators that are incompatible with live cell-fabrication, and ultraviolet (UV) light that is damaging to the cellular DNA. We report here the development of a visible light-based PSL system (VL-PSL), using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as the initiator and polyethylene glycol diacrylate (PEGDA) as the monomer, to produce hydrogel scaffolds with specific shapes and internal architectures. Furthermore, live human adipose-derived stem cells (hADSCs) were suspended in PEGDA/LAP solution during the PSL process, and were successfully incorporated within the fabricated hydrogel scaffolds. hADSCs in PEG scaffolds showed high viability (>90%) for up to 7 days after fabrication as revealed by Live/Dead staining. Scaffolds with porous internal architecture retained higher cell viability and activity than solid scaffolds, likely due to increased oxygen and nutrients exchange into the interior of the scaffolds. The VL-PSL should be applicable as an efficient and effective tissue engineering technology for point-of-care tissue repair in clinic.

3-D Non-UV Digital Printing of Hydrogel Microstructures by Optically Controlled Digital Electropolymerization

“…However, the performance of these traditional methods is limited by several drawbacks: (1) requirement for lithographic masks to define micro/nano scale structures; (2) extremely difficult if at all possible to obtain high-aspect-ratio structures or structures with variable height on the same substrate. Recently, for photo sensitive macromolecules, light-assisted methods allowing dynamically controllable patterning, such as laser scanning lithography [12], [13], and projection printing techniques [14], [15] have been explored by researchers for fabricating PEGDAbased three-dimensional hydrogels. In these methods, the hydrogels are solidified using an UV source and photoinitiator molecules and the hydrogels' pattern are dynamically defined by the designed light images or laser-scanned routes.…”

Rapid prototyping technology and its application in bone tissue engineering

“…With continuous exploration and development, researchers are increasing the types of photocurable polymers and attempting to apply multiple materials (Arcaute et al, 2010). In addition, encapsulation of cells during the process has proved feasible (Chan et al, 2010;Lin et al, 2013). Although this method has not been used in bone tissue engineering, there is a great potential to use this technology in the future.…”

3D Printed Scaffolds as a New Perspective for Bone Tissue Regeneration: Literature Review

“…Due to its pioneering as a printing technique, the first commercial 3D printer was stereo lithographic [61]. Therefore, this technique has been widely used in bioengineering and extensively reviewed [175] [176].…”

“…That is added to the risk of breaking the DNA's double helix with UV radiation [180]. For that, the printing of cells along with the scaffold is not recommended, and so the cells are sedimented in the scaffold after its manufacturing [61].…”

“…Therefore, this technique has been widely used in bioengineering and extensively reviewed [175] [176]. The principle of stereo lithography is based upon photo polymerization of vinyl monomers, which is activated by the decomposition of a photo initiator into free radicals when exposed to UV radiation or visible light [61] [177]- [179].…”