Next Evolution in Organ‐Scale Biofabrication: Bioresin Design for Rapid High‐Resolution Vat Polymerization

Abstract

The field of bioprinting has made significant advancements in recent years and allowed for the precise deposition of biomaterials and cells. However, within this field lies a major challenge, which is developing high resolution constructs, with complex architectures. In an effort to overcome these challenges a biofabrication technique known as vat polymerization is being increasingly investigated due to its high fabrication accuracy and control of resolution (µm scale). Despite the progress made in developing hydrogel precursors for bioprinting techniques, such as extrusion‐based bioprinting, there is a major lack in developing hydrogel precursor bioresins for vat polymerization. This is due to the specific unique properties and characteristics required for vat polymerization, from lithography to the latest volumetric printing. This is of major concern as the shortage of bioresins available has a significant impact on progressing this technology and exploring its full potential, including speed, resolution, and scale. Therefore, this review discusses the key requirements that need to be addressed in successfully developing a bioresin. The influence of monomer architecture and bioresin composition on printability is described, along with key fundamental parameters that can be altered to increase printing accuracy. Finally, recent advancements in bioresins are discussed together with future directions.

Photocross-Linkable and Shape-Memory Biomaterial Hydrogel Based on Methacrylated Cellulose Nanofibres

“…In comparison to the previous studies, where a CNF hydrogel and auxiliary methacrylate components such as gelatine and biopolymer methacrylate were formulated, the current CNF-MA ink showed more suitability in manufacturing relatively soft hydrogel matrix applications. , Thus, further development should be explored to extend the stiffness range of the hydrogel by altering the cross-linker and increasing the DS of MA, which is shown to be a challenge while aiming at relatively higher content of biopolymers in the formulation. Moreover, it is worth pointing out that in response to the strong need for precise deposition of biomaterials and cells, a high-resolution construct with a complex structure can be fabricated by vat polymerization that faces a major challenge in developing soft bioresins for cell encapsulation, , where the CNF-MA inks likely to have potential and will be investigated.…”

Organocatalyzed Phospha‐Michael Addition: A Highly Efficient Synthesis of Customized Bis(acyl)phosphane Oxide Photoinitiators

“…[ 39 , 40 , 41 , 42 , 43 ] Specifically, in the fabrication of medical devices and implants, acylphosphane oxides may play a prominent role. [ 44 , 45 , 46 ] Given the broad range of possible applications of acylphosphane oxides as photoactive components, it is surprising that only few derivatives have been synthesized or commercialized. The phospha‐Michael addition (PMA) between bis(mesitoyl)phosphine, BAPH, and a number of activated olefins can be promoted either by potassium or caesium salts under basic conditions in a biphasic ether/water solvent system.…”

Review on Bioinspired Design of ECM-Mimicking Scaffolds by Computer-Aided Assembly of Cell-Free and Cell Laden Micro-Modules

“…Besides, for the regeneration of tissues featuring oriented architectures, such as nerve, muscle, tendon, ligament, and teeth, scaffolds with aligned pores are needed to direct cell alignment and migration [ 13 , 33 , 34 , 35 ]. CAD-AM techniques have revolutionized TE fabrication processes as they use medical imaging combined with virtual models and automated layer-by-layer manufacturing to control the composition and structure of porous scaffolds to meet patient-specific requirements [ 25 , 26 ]. Composite scaffolds made of biodegradable polyesters, such as poly-lactide-co-glycolide (PLGA) and poly(e-caprolactone) (PCL), loaded with different types of inorganic osteoinductive fillers were developed to mimic the native bone and osteochondral tissues architecture [ 36 , 37 ].…”

“…Several reviews discuss the recent progress of bioprinting in TE scaffold design and fabrication. Most of these works focused their attention on techniques such as extrusion printing and VAT polymerization [ 25 , 26 ]. In contrast, reviews describing current advances of ECM-mimicking scaffolds, and how the CAD-AM of cell-free and cell laden modular tissue units can be used to meet these challenges, are scarce.…”