Improving Printability of Digital-Light-Processing 3D Bioprinting via Photoabsorber Pigment Adjustment

Abstract

Digital-light-processing (DLP) three-dimensional (3D) bioprinting, which has a rapid printing speed and high precision, requires optimized biomaterial ink to ensure photocrosslinking for successful printing. However, optimization studies on DLP bioprinting have yet to sufficiently explore the measurement of light exposure energy and biomaterial ink absorbance controls to improve the printability. In this study, we synchronized the light wavelength of the projection base printer with the absorption wavelength of the biomaterial ink. In this paper, we provide a stepwise explanation of the challenges associated with unsynchronized absorption wavelengths and provide appropriate examples. In addition to biomaterial ink wavelength synchronization, we introduce photorheological measurements, which can provide optimized light exposure conditions. The photorheological measurements provide precise numerical data on light exposure time and, therefore, are an effective alternative to the expendable and inaccurate conventional measurement methods for light exposure energy. Using both photorheological measurements and bioink wavelength synchronization, we identified essential printability optimization conditions for DLP bioprinting that can be applied to various fields of biological sciences.

Efficient Myogenic/Adipogenic Transdifferentiation of Bovine Fibroblasts in a 3D Bioprinting System for Steak‐Type Cultured Meat Production

“…Several parameters, including the mechanical speed, light intensity, light exposure time, and wavelength were fixed to establish the optimal polymerization conditions to print microcontrollable structures. The problem of mismatch between the DLP light wavelength and the absorbance of the prepolymer solution was solved by using a yellow photoabsorber [ 42 ] (Figure S1d , Supporting Information). The DLP light intensity was set to the lowest intensity possible for printing (1.97 mW cm −2 ) to minimize cell stress.…”

“…To produce cultured meat hydrogel at the cm scale, this study aimed to develop ways to optimize bioink using photocrosslinkable materials for DLP printing and to demonstrate the feasibility of producing cultured meat by differentiating fibroblasts into muscle and fat cells followed by proliferation. By using a tartrazine as a photoabsorber [ 42 ] in the bioink using GelMA as a homopolymer, it was synchronized with the light wavelength band of the DLP printer. The limitations of the cm‐scale hydrogel production due to the mechanical properties of GelMA were solved through 3D modeling by introducing microchannels and using buoyancy.…”

Comparison of thickness, gap width and translucency for 3D-printed and thermoformed clear aligners: A micro-CT analysis

“…38 In addition, the dimensional accuracy of a 3D-printed appliance is affected by factors including light intensity, exposure time, and the properties of printing materials such as light-blocking pigment concentration and light penetration. 36,39,40 Consequently, if the optimal 3D printing conditions and design parameters suited for the materials and printer types are periodically calibrated, the error related to the thickness change and unstable adaptability could be improved.…”

State-of-the-art techniques for promoting tissue regeneration: Combination of three-dimensional bioprinting and carbon nanomaterials

“…Image (c) was reprinted from Micromachines , 10, Pan Y, Zeng L, Simulation and validation of droplet generation process for revealing three design constraints in electrohydrodynamic jet printing, 94, Copyright (2019), with permission from MDPI [ 20 ] . Image (e) was reprinted from International Journal of Molecular Sciences , 23, Seo JW, Kim GM, Choi Y, et al, Improving printability of digital-light-processing 3D bioprinting via photoabsorber pigment adjustment, 5428, Copyright (2022), with permission from MDPI [ 29 ] .…”

“…The printing process uses a dynamic mask carrying a design pattern to transmit the light pattern to the substrate and a layering software to slice the 3D digital model to a certain thickness. Liquid crystal display, digital micromirror device, and spatial light modulator have been employed as dynamic masks in DLP printing [ 29 ] . DLP offers a remarkable advantage over DBB and EBB technologies in terms of printing speed, wherein there is no increase in printing time despite a more complex structure.…”