Protein-Based 3D Biofabrication of Biomaterials

Abstract

Protein/peptide-based hydrogel biomaterial inks with the ability to incorporate various cells and mimic the extracellular matrix’s function are promising candidates for 3D printing and biomaterials engineering. This is because proteins contain multiple functional groups as reactive sites for enzymatic, chemical modification or physical gelation or cross-linking, which is essential for the filament formation and printing processes in general. The primary mechanism in the protein gelation process is the unfolding of its native structure and its aggregation into a gel network. This network is then stabilized through both noncovalent and covalent cross-link. Diverse proteins and polypeptides can be obtained from humans, animals, or plants or can be synthetically engineered. In this review, we describe the major proteins that have been used for 3D printing, highlight their physicochemical properties in relation to 3D printing and their various tissue engineering application are discussed.

Current Trends on Protein Driven Bioinks for 3D Printing

“…Thanks to its versatile physicochemical properties, gelatin allows the development of both high and low viscosity gelatin based bioinks. The gelling can be controlled by temperature, because the hydrogen bonds that hold the triple-helix conformation of gelatin together are weakened by increased temperature, generally above 30 °C, which facilitates optimization of the flow behavior during bioprinting [ 40 , 54 ]. Gelatin concentrations in a bioink can range from 1–20%, being 5% w / v the most common value [ 3 ].…”

“…Among these, protein-based materials such as collagen [ 28 , 29 ], fibrin [ 30 , 31 , 32 ], keratin [ 33 , 34 ], or decellularized extracellular matrix-based materials [ 35 , 36 ], have been broadly used in several biomedical fields and more recently integrated in 3D bioprinting systems due to its abundance, low cost, tunable physicochemical, mechanical and biological properties and excellent biocompatibility and biodegradability [ 25 , 27 , 37 ] While these materials are generally more difficult to manipulate, often possessing poor mechanical properties, or unpredictable behavior when printed, they can provide a better environment for cell growth as a result of specific encoded designs, i.e., amino acid sequence information which guides the construct assembly and mimic the extracellular matrix (ECM) [ 17 , 18 , 21 , 37 ]. Protein-based materials can additionally be used to modify several rheological and biochemical properties of bioinks, allowing for higher construct fidelity [ 38 , 39 , 40 ]. A final consideration, of special importance in modern science, is that these materials are both renewable, and very environmentally-friendly, particularly when compared to fossil-derived synthetic polymers [ 40 ].…”

“…Protein-based materials can additionally be used to modify several rheological and biochemical properties of bioinks, allowing for higher construct fidelity [ 38 , 39 , 40 ]. A final consideration, of special importance in modern science, is that these materials are both renewable, and very environmentally-friendly, particularly when compared to fossil-derived synthetic polymers [ 40 ]. Nonetheless, they can be highly sensitive (frequently thermolabile) and therefore difficult to extract and purify.…”

“…However, this technique still comes with some drawbacks like the lack of available bioinks, and the high shear stress cells can get exposed to, which can reduce cell viability in the final construct [ 41 ]. Thus, experimenting with different crosslinking methods, material formulation and additional components to improve the overall mechanical, rheological, physicochemical and biological properties is crucial in these systems [ 3 , 40 ].…”

Enhancing Peptide Biomaterials for Biofabrication

“…Historically, lab-made scaffolds have been synthesised from modified proteins or long-chain polysaccharides [ 62 , 63 , 64 ]. However, protein materials sourced from animals suffer from batch-to-batch inconsistency and xenogeneic protein transfer issues, limiting translation to clinical settings [ 65 , 66 , 67 ].…”