Freeform Perfusable Microfluidics Embedded in Hydrogel Matrices

Abstract

We report a modification of the freeform reversible embedding of suspended hydrogels (FRESH) 3D printing method for the fabrication of freeform perfusable microfluidics inside a hydrogel matrix. Xanthan gum is deposited into a CaCl2 infused gelatine slurry to form filaments, which are consequently rinsed to produce hollow channels. This provides a simple method for rapid prototyping of microfluidic devices based on biopolymers and potentially a new approach to the construction of vascular grafts for tissue engineering.

Microvascular Tissue Engineering—A Review

“…In addition to direct deposition of the scaffold material, extrusion-based printing for vascular tissue engineering often uses sacrificial inks that are embedded into the target scaffolding material and subsequently removed. The sacrificial ink can be deposited to a plain surface prior to embedding [ 115 , 119 , 120 , 121 , 122 ] or directly into a support bath that remains in place after ink removal [ 123 , 124 , 125 , 126 ]. In addition to the general properties that apply to microextrusion, support bath printing extends the range of appropriate materials and possible geometries of the final scaffolds.…”

“…However, the support bath itself must also meet certain requirements, namely, (1) it should have “self-healing” properties, and continuously fill the void created by a moving nozzle; (2) the nozzle should displace only the material in its direct vicinity without disturbing the bulk material; and (3) if the support bath needs to chemically stabilize the deposited filaments, it should not prevent consecutive filaments from merging together on contact. These requirements are typically controlled by the composition and granulation of the support bath [ 108 , 124 , 125 , 126 ].…”

Fabrication techniques of biomimetic scaffolds in three‐dimensional cell culture: A review

“…The rheological analysis shows that gelatin support shows Bingham plastic behavior (viscous fluid at high stress; Hinton et al, 2015). In another study of FRESH, xanthan gum is deposited into calcium chloride infused gelatin slurry to form filaments/hollow channels (hydrogels) that resemble vascular structures necessary for tissue engineering applications (Štumberger & Vihar, 2018). Applicability of this technique has potential in greater innovations and in areas related to implantation technology that require smoother surfaces for biocompatibility.…”

Tissue Engineering and Regenerative Medicine 2019: The Role of Biofabrication—A Year in Review

“…In a recent study, xanthan gum was deposited into a CaCl 2 -infused gelatin to form sacrificial channels to rapid prototype microfluidic platforms with earlobe-shaped channels. 24 Using this method, the authors created complex 3D structures, stable enough to support themselves as well as complex channel geometries that were evenly perfusable. 24 To further develop potential new vascular tissues, Ji et al deposited a sacrificial ink between several layers of a cell-laden oriented hydrogel bioink to therefore produce perfusable channels.…”

“…24 Using this method, the authors created complex 3D structures, stable enough to support themselves as well as complex channel geometries that were evenly perfusable. 24 To further develop potential new vascular tissues, Ji et al deposited a sacrificial ink between several layers of a cell-laden oriented hydrogel bioink to therefore produce perfusable channels. Briefly, they constructed methacrylate alginate or methacrylate hyaluronic acid hydrogels with incorporated sacrificial ink (Pluronic), which was removed after curing.…”