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Elemoso, et al.
disease – scurvy that was caused by chronic vitamin
C deficiency as a result of the lack of fresh fruit
and vegetables. This condition happened when
the seafaring people were at sea continuously for
probably more than 3 months, at some stage in the
voyaging and the price was more than 2 million
lives . This case shows that humans have to
[35]
prepare for investigating not only new deep space
but also possible risks and dangers during these
flights.
3.3 Investigation of space radiation effect on
human tissues
Another separate, essential branch of space
biological science is space radiation studies.
Recently, the possibility of creating permanent
bases on the Moon, sending manned spacecraft to
Mars, and establishing planetary settlements on
the planet has been in discussion more frequently
according to the vast experience of habitability
of space. Space radiation is known to have a
negative effect on the human body, especially
in space flights outside the earth’s protective
magnetosphere. Bioprinting technology allows
to create radiation-sensitive organs, so-called
sentinel organs, as models for further studies of
radiation effects.
4 Drug discovery
The pharmaceutical industry could strongly
benefit from having means of early detection
of negative side effects of potential drugs. This
allows pharmacologists to save time and money
on formulations as well as cases when a side effect
was only discovered when the drug is already in
the market but needs to be recalled, with obvious
legal and financial ramifications.
2D-based assays are currently the main
technology being used for pre-clinical studies.
The problem with this technology is that in two
dimensions, the cells have a limited amount
of contacts between themselves. Most of their
contacts are with the culture medium or the surface
they are on. This in turn leads to limited modeling
of real human tissue interactions (signaling,
biomarkers, etc.) This is the reason why the drugs
International Journal of Bioprinting (2020)–Volume 6, Issue 3
tested in 2D fail when tested in vivo. Finally, a new
alternative has become available – tests 3D tissue
and organ constructs. They can also be used for
testing cosmetic formulations as an alternative to
animal tests which are getting banned in different
jurisdictions (like the EU since 2013).
The increased effectiveness of 3D cultures
comparing to 2D analogs is widely accepted.
However, the question on how to obtain
standardized fabrication methods that allow
reproducibility of constructs, rapidness, and cost-
effectiveness required for drug testing remains.
3D bioprinting with its automation capabilities
and possibility to form complex structures seems
the most likely candidate for providing the answer.
Other advantages of 3D bioprinting in comparison
to other fabrication methods include the ability
to create channels for vascularization inside the
constructs as well as allowing coculture to form
heterotypic constructs under the conditions similar
to a typical tissue environment. This increases
interest in applying 3D bioprinting to various
stages drug discovery (Figure 2) [36-38] .
Biofabrication strategies that are being used
include rotating flask methods, liquid overlay,
hanging drop, and magnetic levitation. Manual cell
seeding or fabrication of a mold are typically used
for these methods . Bioprinting offers higher
[39]
precision, resolution, and accuracy in comparison
to the methods listed above . Other advantages
[40]
of bioprinting include easier fabrication of
spatially-patterned coculture models, low risk
of cross-contamination while handling different
cell types (in a limited physical space), precise
control over delivery of growth factors and genes,
and controlled architecture with high-throughput.
Bioprinting also enables fabrication of constructs
with desired pore sizes associated with a specific
type of tissue as well as a controlled architecture.
A crucial advantage of bioprinting is that it can
be utilized under physiologically-amenable
conditions (e.g., pH, humidity, and temperature),
while adding genes and proteins that help
modulate the behavior of cells. Moreover, using
magnetic levitation for bioprinting of tissue
spheroids improves the throughput and resolution
of bioprinted constructs .
[41]
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