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Parfenov, et al.
national regulatory agencies. In the meantime, A B
there is a growing body of evidence indicates
that gadolinium can induce kidney fibrosis in
human patients. Moreover, it has been shown
that gadolinium blocks calcium channels and
causes toxicological effects on cells in vitro and
in vivo [20-23] . The reduction of gadolinium salts Figure 1. “Organ.Aut” is a magnetic levitational
concentration practically enables the complete bioassembler. (A) Design of “Organ.Aut,” (B) the
elimination of undesirable toxic effects, but it external view of “Organ.Aut.”
could compromise the magnetic levitation. In
other words, cells are alive, but they could not and conduct six experiments simultaneously. For
levitate. From another point of view, the increasing the outer envelope, aluminum alloy D16-T was
concentration of gadolinium salts not only enables selected. Each pair of magnets (Figure 2C) was
magnetic levitation but also induces a significant designed in such a way to form magnetic well in
cytotoxic effect. the center .
[25]
Thus, cells can levitate, but they are dying in The magnetic field was shielded to ensure the
a toxic concentration of gadolinium. There are safe operation of the magnetic bioassembler on the
three theoretically possible, potential strategies International Space Station (ISS). Thus, individual
to solve this dilemma: (i) The development of screens were created (position 1, Figure 2G)
non-toxic gadolinium salts; (ii) the use of a high from magnetically conductive stainless steel
magnetic field to achieve a significant reduction of and connected to the inner case of the magnetic
gadolinium salt concentration; and (iii) performing bioassembler. Furthermore, to ensure that various
label-free magnetic levitational bioassembly under metal objects did not get into the magnetic
the condition of microgravity in space to decrease bioprinter during its operation, unique covers
gadolinium salt concentration. We systematically with a diaphragm-based locking mechanism were
tried to address and explore all three strategies. added (Figure 2E). The material of these covers is
First, we failed to find non-toxic gadolinium or its magnetically conductive stainless steel.
adequate paramagnetic media alternative. Second, Three cameras with special macro lenses were
we were able to perform label-free magnetic provided to visualize the biofabrication process.
levitational bioassembly in the high magnetic field For this, Go Pro Hero 4 Silver (Figure 2F)
with significant (more than 100 times) reduction having certificates for the use on ISS were used.
of paramagnetic gadolinium salts . We also Furthermore, a lighting unit which is powered by
[24]
successfully performed a label-free magnetic 6 A.A. batteries was provided for illumination
levitational bioassembly at the microgravity during the process of video recording (Figure 2D).
conditions in space . A separate task was the development of special
[25]
6 Design and construction of bioassembler cuvettes for safe transportation of biological objects
to the ISS, biological experiments, and fixing the
“Organ.Aut” is a magnetic bioassembler that was fabricated constructs for further analysis (histological
created to study the possibility of formative 3D sections, etc.). Functionally, the cuvette is a system
biofabrication of tissue structures using the method consisting of two V1 containers (the containers
of self-assembly of living tissues and organs in have the same volume but different contents) and
microgravity (Figure 1A and B). The central part the V2 biofabrication chamber. Between containers,
of the magnetic bioassembler is the inner case, with there are valve assemblies that prevent fluid from
six pairs of magnets placed inside (Figure 2B). moving from containers V1 to chamber V2 without
The shape of the case (Figure 2A) made it possible pressing the pistons P (Figure 3A). The design
to minimize the overall dimensions of the device of the cuvette was made of a transparent material

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