Page 23 - IJB-9-1

International Journal of Bioprinting Biocompatible materials and Multi Jet Fusion

easy customization, scalability, rapid manufacturing, and FDM and SLS for tissue engineering applications, whereas
material tuning [1-4] . Polymer-based material systems are FDA-approved PLGA copolymers are used by FDM to
widely adopted by 3D printing for their abundant availability, print parts for clinical use. Nylon can be 3D-printed using
unparalleled multifunctionality, and versatility associated FDM, SLS, and Multi Jet Fusion (MJF), and it is best suited
[35]
with processability and performance [5,6] . The range of for industrial and engineering applications .
polymers used in 3D printing encompasses thermoplastics, Powder bed fusion (PBF) is a promising 3D printing
thermosets, functional polymers, polymer blends, composite technique that offers high-throughput manufacturing of
elastomers, and hydrogels [7-9] . For instance, 3D printing biocompatible bioreactors [17,36] . SLS and MJF, two most
techniques, such as fused deposition modeling (FDM), popular PBF 3D printing technologies, have attracted
material jetting, and selective laser sintering (SLS) use considerable attention from academic and industrial
thermoplastics, while stereolithography (SLA) and direct organizations due to their rapid printing speed and
ink writing use photocurable thermosetting polymers [10,11] . compatibility with a variety of polymer materials [37,38] .
3D printing has improved material properties and enhanced Many SLS-printed polymer (such as PCL and PLLA)
the functionality of the printed construct [12-14] . 3D constructs were evaluated for biocompatibility due
3D printing has emerged as an effective tool for many to their ability to promote cell adhesion and support
biomedical applications such as biocompatible implants, cell differentiation [39,40] . Other non-toxic materials
3D organ models and organoids, drug delivery, and tissue such as thermoplastic polyurethane and polyamide
regeneration [15-17] . Considerable effort has been dedicated nylon 12 (PA-12) were also printed by SLS for different
toward 3D printing of bioreactors, which provide an bioapplications [41-43] . With a continuous influx of new
opportunity to design and construct intricate, custom- printable materials, it is important to understand both the
made designs with well-defined architectures . The advantages and limitations of the new printing technologies
[18]
biocompatibility of a 3D-printed bioreactor influences and materials.
its role in the sustenance of cell functions. At times, the MJF is an innovative 3D printing technique developed
printed material may not be conducive for cell growth. by Hewlett-Packard (HP) that works similar to a binder jet
Many studies have documented in vitro cellular inhibition technique in using a powder delivery system. However, the
due to the toxic residues in solidified polymers post- unique build style includes incorporation of a multi-agent
printing [19-22] , while some have attempted to mitigate such inkjet system within the PBF process and makes it different
effects by developing post-printing treatment such as from other PBF technologies [43,44] . The printing process
ultraviolet light exposure [23,24] . Some 3D-printed in vivo involves the application of a thin layer of powder materials
devices have been shown to cause infections and allergic on the build plate followed by selective deposition of the
responses in patients [25,26] . Therefore, it is important to fusing agent onto areas, where the powder particles are
examine biocompatibility of 3D-printed materials to intended to fuse, and the addition of detailing agent at
minimize the effect of failure in their performance as the contour of the patterns to create smooth surfaces. The
3D-printed bioreactors. powder layer on exposure to the infrared energy source
allows the area of the fusion agent to fuse and forms the
Selecting the optimal printing technique and material part. This technique is capable of fabricating parts with
is imperative to maximizing the chance of success of a 3D excellent dimensional precision and low porosity .
[45]
printing process. Several bioreactors have been 3D-printed
by FDM due to its low cost, high speed, simplicity and A recent evaluation of mechanical properties and
capability of printing various biomaterials, or by SLS printing characteristics suggest that MJF-printed
which demonstrated good isotropic mechanical properties specimens have a better surface finish, high strength, and
[43]
with complex geometries, and required no support [27-29] . wear resistance strength than SLS-printed counterparts .
Other methods such as SLA and its variants, namely, In addition, MJF printing has also shown the least impact
projection micro SLA, showed a very good resolution, on the environment and human health, allowing for
accuracy, and printing time independent of the complexity concurrent fabrication of different designs and large-scale
[35]
of designs [30-32] . Commonly used polymer materials for green manufacturing compared to other technologies .
3D printing include acrylonitrile butadiene styrene, PA-12 is an inexpensive, bio-based, non-toxic, and
poly(caprolactone) (PCL), poly(D,L-lactic acid-co-glycolic semi-crystalline polymer for sustainable 3D printing. It
acid) (PLGA), poly ether ester ketone, polylactic acid, offers outstanding impact resistance, good resolution,
polycarbonate, polyetherimide, and nylon [8,10,33] , and the strong chemical resistance, thermal stability, durability, and
selection of material depends on the application of the lowest moisture absorbance of all the polyamides [46,47] . Due
end product . For example, PCL is commonly utilized by to its mechanical properties and excellent biocompatibility
[34]

Volume 9 Issue 1 (2023) 15 https://doi.org/10.18063/ijb.v9i1.623