Projection-Based 3D Printing of Cell Patterning Scaffolds with Multiscale Channels

Abstract

To fully actualize artificial, cell-laden biological models in tissue engineering, such as 3D organoids and organs-on-a-chip systems, cells need to be patterned such that they can precisely mimic natural microenvironments in vitro. Despite increasing interest in this area, patterning cells at multiscale (∼10 μm to 10 mm) remains a significant challenge in bioengineering. Here, we report a projection-based 3D printing system that achieves rapid and high-resolution fabrication of hydrogel scaffolds featuring intricate channels for multiscale cell patterning. Using this system, we were able to use biocompatible poly(ethylene glycol)diacrylate in fabricating a variety of scaffold architectures, ranging from regular geometries such as serpentine, spiral, and fractal-like to more irregular/intricate geometries, such as biomimetic arborescent and capillary networks. A red food dye solution was able to freely fill all channels in the scaffolds, from the trunk (>1100 μm in width) to the small branch (∼17 μm in width) without an external pump. The dimensions of the printed scaffolds remained stable over 3 days while being immersed in Dulbecco's phosphate-buffered saline at 37 °C, and a penetration analysis revealed that these scaffolds are suitable for metabolic and nutrient transport. Cell patterning experiments showed that red fluorescent protein-transfected A549 human nonsmall lung cancer cells adhered well in the scaffolds' channels, and showed further attachment and penetration during cell culture proliferation.

Engineering of Hydrogel Materials with Perfusable Microchannels for Building Vascularized Tissues

“…Attributed to the versatility of stereolithography, Xue et al printed a capillary network with biomimetic irregular bifurcations and channel sizes in PEGDA. The perfusion of the red food dye in the network from the trunk (over 1 mm in width) to small branches (about 17 μm in width) was also showed ( Figure A) . Though xy ‐resolution can be well adjusted by improving the pixels of DMD, the z ‐axis resolution of a thick 3D structure was limited.…”

“…A) Scheme of stereolithography platform and the perfusion of dyes solutions in the printed channels inside PEGDA. Reproduced with permission . Copyright 2018, American Chemical Society.…”

From Arteries to Capillaries: Approaches to Engineering Human Vasculature

“…Reproduced with permission. [ 147 ] Copyright 2018, American Chemical Society. D) 3D printed hierarchically branched tubular networks.…”

“…While this technique enables generation of complex structures in one short pulse of light (a few seconds), its ability to generate vasculature in thick 3D tissues is limited to the depth of light penetration into the polymer. [ 147 ]…”

Organ-on-a-chip: recent breakthroughs and future prospects

“…Microfluidics control cell patterning for the construction of in vitro physiological models with complex geometries. Surface modifications [41], templates [42], and 3D printing [43] contribute to cell patterning on the chip. The 3D printing method enables multi-scale cell patterning by permitting the formation of hydrogel scaffolds with complex channels.…”