On‐demand three‐dimensional freeform fabrication of multi‐layered hydrogel scaffold with fluidic channels

Abstract

One of the challenges in tissue engineering is to provide adequate supplies of oxygen and nutrients to cells within the engineered tissue construct. Soft-lithographic techniques have allowed the generation of hydrogel scaffolds containing a network of fluidic channels, but at the cost of complicated and often time-consuming manufacturing steps. We report a three-dimensional (3D) direct printing technique to construct hydrogel scaffolds containing fluidic channels. Cells can also be printed on to and embedded in the scaffold with this technique. Collagen hydrogel precursor was printed and subsequently crosslinked via nebulized sodium bicarbonate solution. A heated gelatin solution, which served as a sacrificial element for the fluidic channels, was printed between the collagen layers. The process was repeated layer-by-layer to form a 3D hydrogel block. The printed hydrogel block was heated to 378C, which allowed the gelatin to be selectively liquefied and drained, generating a hollow channel within the collagen scaffold. The dermal fibroblasts grown in a scaffold containing fluidic channels showed significantly elevated cell viability compared to the ones without any channels. The on-demand capability to print fluidic channel structures and cells in a 3D hydrogel scaffold offers flexibility in generating perfusable 3D artificial tissue composites.

Hydrogel-based microfluidics for vascular tissue engineering

“…Here we first focused on the evaluation of optimum gel properties for induction of a cellular lumenalized network by co-culture of vasculogenic cells. However, the principle of a sacrificial material interconnected capillary network formation based on utilization of gelatin [37] or sugar [35] is certainly applicable to the approach described in this paper. Using a combination of photolithography and soft lithography methods, it should be possible to fabricate complex interconnected microchannel networks from a sacrificial material and apply it for embedding within cell laden PEGylated fibrin gels.…”

3D-printed biological organs: medical potential and patenting opportunity

“…3D bioprinting with phase-changing hydrogel [5][6][7][8][9]11,12] --Liquid state, phase-changing hydrogel precursors are printed at high-spatial resolution. --Various types of cells, prepared in a liquid-state suspension, are printed separately and embedded into the hydrogel.…”

In vitro skin three-dimensional models and their applications

“…As 3D bioprinting has the ability to manufacture the 3D structures in an on-demand fashion, it has been applied to create various biomimetic structures, such as fluidic channels [56], vascular-like structures [49], growth-factor releasing matrices [57], 3D neural tissues [58], and tumor cell-bearing tissues for angiogenesis models [59]. With regard to bioprinted skin, complex skin tissues with dermal and epidermal layers containing keratinocytes, melanocytes and fibroblasts were generated [49,58,60,61].…”