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Materials Science in Additive Manufacturing 2D/3D visualization software for bioprinting

fabrication methods, 3D bioprinting methods that use The last in the umbrella of 3D printing techniques is
multiple materials enable the fabrication of customized dubbed VAT polymerization. Under it falls a number of
and complex tissues and organs, which facilitates the categories including stereolithography (SLA) and digital
[5]
use of this technology in clinical and pharmaceutical light processing (DLP) . In both these technologies, a
applications . According to Liu et al., the spatial photo-initiated liquid material is solidified using a laser. To
[3]
locations and arrangement of biocomponents in the produce the overall 3D printed structure, the liquid is set
printed constructs are highly critical to achieve functional against a platform which is raised after each layer of liquid
tissues . Customized computer-aided design (CAD) and is solidified by the laser . The difference between SLA and
[11]
[4]
3D bioprinting give an additional advantage when used DLP, however, is that the former shines the laser at specific
with cell-laden biomaterials, allowing for better control areas to produce the layers. In contrast, DLP instead shines
of the distribution of cells and biomolecules in 3D printed the laser throughout the entire area and is only selective
constructs . A comprehensive review paper by Kim et al. due to a mask between the laser and liquid. The downside
[3]
discusses the various 3D bioprinting techniques in general associated with both these techniques, unfortunately, is the
(i.e., using a single extruded material) as well as with inability to include cells during the printing process . As
[11]
multiple extruded materials . In addition, it shares the such, other following protocols are needed to seed the cells
[3]
perspectives and future directions for developing state-of- in their intended locations.
the-art techniques of multi-material 3D bioprinting. One example of a bioprinter was illustrated by Liu
There are currently three broad categories, in which et al. in which he designed a multi-material extrusion
3D printing techniques find themselves in: material bioprinting platform that can accurately extrude and
extrusion, material jetting, and VAT polymerization . As switch between several bioinks continuously and rapidly
[5]
of today, extrusion-based printing is the most commonly for fast complex tissue fabrication . Another 3D printing
[4]
used printing technique. Its process of usage includes the device is illustrated in the research study by Miri et al.,
loading of biomaterials into their respective cartilages and within which the development of a microfluidic device that
their subsequent extrusions from a nozzle using either can also rapidly switch between different hydrogel bioinks
[12]
mechanical or pressure-based forces. Since the nozzle is while maintaining high spatial resolution is elucidated .
held above and moved along a predetermined platform, Interestingly, Ng et al. addressed the potential and
its motion allows the user to print a 3D object visualized advantages of adopting deep learning techniques into
by a viewing program on a connected computer. Some the 3D printing process; this was done in the intention
advantages of this technique include the ability to extrude of fabricating better biomimetic patient-specific tissues/
bioinks laden with high cell density counts (hence their organs . Similarly, An et al. highlighted the benefits
[13]
popularity in 3D cell culturing protocols), the capacity to lay of utilizing machine learning and digital twin of human
those cells in specific areas within the overall 3D structure tissues to mimic the 3D printing process and maximize the
[14]
during its creation, as well as the relative cost efficiency of bioprinting efficiency and usage of biomaterials .
this technique as far as its customizability is concerned . In the standard 3D printing process, a geometric code
[6]
Material jetting is another procedure in which bioprinted (G-code) file (acquired from a slicer software) gives the
objects can be made, with inkjet techniques being widely directional map in terms of the desired 3D model’s XYZ
used. Considered one of the earliest established bioprinting planes to the 3D printing software. In other words, the
processes, this method includes a downstream droplet G-code file contains the geometrical description of a 3D
ejection induced by a volumetric change upstream of the model that allows the instruction of the 3D printer in its
nozzle . The formation of the droplet is most commonly printing in a layer-by-layer fashion . If the G-code holds
[7]
[15]
generated through piezo-electric or thermally induced any syntax or semantic errors, the 3D model might not
bubbles. For more in-depth information, refer to other be correctively 3D printed . One way to detect G-code
[16]
papers [8-10] . Some of the pros associated with this technique errors is by viewing and/or simulating its attributed
are attributed to its high printing speeds, low costs, and 3D model based on its code; such a program is called a
its contactless nature (thus avoiding contamination issues). G-code visualizer/simulator . There are already plenty
[16]
Unfortunately, since the viscosity of the bioink cannot be of 3D printing software programs with the features of
above a certain value, inks laden with a high volume of viewing the 3D model and simulating the 3D printing
cells cannot be utilized in the creation of the 3D object . process; one instance of this is the Repetier-Host Software.
[6]
As such, this method, as opposed to the aforementioned Another example of this was by Ueng et al., in which a
extrusion-based bioprinting procedure, is not optimal for preview system for 3D printing was developed that utilizes
printing biologically included structures. G-code and some graphic techniques to efficiently display

Volume 1 Issue 3 (2022) 2 https://doi.org/10.18063/msam.v1i3.19