3D bioprinting of biomimetic aortic vascular constructs with self‐supporting cells

Abstract

Cardiovascular diseases are the leading cause of deaths throughout the world. Vascular diseases are mostly treated with autografts and blood vessel transplantations. However, traditional grafting methods have several problems including lack of suitable harvest sites, additional surgical costs for harvesting procedure, pain, infection, lack of donors, and even no substitutes at all. Recently, tissue engineering and regenerative medicine approaches are used to regenerate damaged or diseased tissues. Most of the tissue engineering investigations have been based on the cell seeding into scaffolds by providing a suitable environment for cell attachment, proliferation, and differentiation. Because of the challenges such as difficulties in seeding cells spatially, rejection, and inflammation of biomaterials used, the recent tissue engineering studies focus on scaffold-free techniques. In this paper, the development of novel computer aided algorithms and methods are developed for 3D bioprinting of scaffold-free biomimetic macrovascular structures. Computer model mimicking a real human aorta is generated using imaging techniques and the proposed computational algorithms. An optimized three-dimensional bioprinting path planning are developed with the proposed self-supported model. Mouse embryonic fibroblast (MEF) cell aggregates and support structures (hydrogels) are 3D bioprinted layer-by-layer according to the proposed self-supported method to form an aortic tissue construct.

Three-dimensional bio-printing

“…The mechanical properties and bio-properties of hydrogel need to be modified for printing and cell survival. At present, during printing and crosslinking there will be some cell death with a wide range (~2%-40%) because the cells are outside various natural environment [65,67,68]. There are chemical and physical ways to crosslink hydrogels.…”

Roles of support materials in 3D bioprinting – Present and future

“…It is almost impossible for bioprinting to fabricate this structure without using support. However, comparing the materials that have been used in used deposition modelling (FDM) with hydrogels or bioinks for bioprinter, the mechanical strength of the FDM materials is typically stronger [4][5][6][7][8][9][10][11][12][13][14][15][16] . The current hydrogels that have been used with bioprinter are too soft to hold the shape.…”

Current developments in 3D bioprinting for tissue engineering

“…Bioprinting vascularization can be divided in two groups: bioprinting the actual vessels [55] and bioprinting tissue with nutrient channels [54]. By building up a vessel layer by layer, it is possible to create the intricate structures of hollow, branched blood vessels [6,56] and larger self-supporting structures [57]. Hinton et al [2] showed they can create an entire, full-size, perfusable human right-hand coronary arterial tree out of alginate using FRESH printing.…”