Current Advances in 3D Bioprinting Technology and Its Applications for Tissue Engineering

Abstract

Three-dimensional (3D) bioprinting technology has emerged as a powerful biofabrication platform for tissue engineering because of its ability to engineer living cells and biomaterial-based 3D objects. Over the last few decades, droplet-based, extrusion-based, and laser-assisted bioprinters have been developed to fulfill certain requirements in terms of resolution, cell viability, cell density, etc. Simultaneously, various bio-inks based on natural–synthetic biomaterials have been developed and applied for successful tissue regeneration. To engineer more realistic artificial tissues/organs, mixtures of bio-inks with various recipes have also been developed. Taken together, this review describes the fundamental characteristics of the existing bioprinters and bio-inks that have been currently developed, followed by their advantages and disadvantages. Finally, various tissue engineering applications using 3D bioprinting are briefly introduced.

3D bioprinted organ‐on‐chips

“…Solidifiable materials, including ion-crosslinkable hydrogels, temperature-sensitive polymers, and photopolymer bioinks are commonly used materials for 3D bioprinting. [2,158] The bioink can be derived from natural sources, such as alginate (also termed algin or alginic acid), carrageenan (also termed carrageenin), gellan gum, agar (also termed agarose), collagen, fibrin, gelatin, silk, fibrinogen, chitosan, methyl cellulose (derived from cellulose), and hyaluronan, [159][160][161][162] or it can be derived synthetically, such as poloxamer (also termed Pluronic), Matrigel, poly(caprolactone) (PCL), poly(ethylene glycol) (PEG), GelMA, poly(vinyl alcohol) (PVA), poly(lactic acid) (PLA), and poly(lactic-co-glycolic acid) (PLGA). [161,162] Alginate (a natural polymer extracted from brown seaweeds) is a cost-efficient option for bioink preparation with no toxicity, and good printability, yet with low cellular adhesion and slow degradation.…”

“…[170] PVA is a biocompatible, watersoluble polymer with suitable hydrophilicity and toughness for bioink preparation that has limitations in the adhesion of cells. [161,171] PEG (one of the FDA-approved materials for medical applications) is a biocompatible and easily modifiable polymer, well known for usage as sacrificial bioink, with limitations in mechanical strength and cell adhesion. [161,169] Furthermore, GelMA is a biocompatible and biodegradable option for the preparation of bioinks, where a crosslinking process with UV light is needed that can adversely affect cell viability, although visible-light options are becoming more broadly adopted.…”

“…[161,171] PEG (one of the FDA-approved materials for medical applications) is a biocompatible and easily modifiable polymer, well known for usage as sacrificial bioink, with limitations in mechanical strength and cell adhesion. [161,169] Furthermore, GelMA is a biocompatible and biodegradable option for the preparation of bioinks, where a crosslinking process with UV light is needed that can adversely affect cell viability, although visible-light options are becoming more broadly adopted. [161,172] One of the most important factors in selecting one of these materials for the preparation of the desired OOC is the crosslinking mechanism, which should be chosen to be harm-less to the cells to be loaded into the bioink, based on the fabrication method (photosensitive bioinks for light-induced methods and bioinks with shear-thinning ability for nozzlebased approaches).…”

3D Bioprinting of In Vitro Models Using Hydrogel-Based Bioinks

“…Thermo-responsive hydrogels undergo sol-gel conversion due to the network alteration in response to temperature changes. Various thermo-responsive bioinks such as gelatin and PF-127 play a major role in the deposition ability of bioinks [140]. These are added to bioink compositions to improve their deposition capacity, or to print supports with sacrificial bioinks that help create architecture with overhang structures.…”

Natural Hydrogel-Based Bio-Inks for 3D Bioprinting in Tissue Engineering: A Review

“…The use of bio-ink containing other biomaterials may provide additional mechanical support for the bioprinted cells, helping them to organize, migrate and differentiate autonomously to form functional tissues [ 7 ]. It is, therefore, possible to manufacture physiologically complex human heterogeneous tissues in a personalized manner.…”