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Magnetic levitational bioassembler
constructs. There are already several published uses processes such as injection molding, die
well-written reviews describing label-based casting, pressing, and stamping to create materials
Mag-TE [15-17] . into the desired shape. In traditional formative
The main limitation of this promising manufacturing, molds are applied to achieve the
technology is the employment of potentially toxic desired shape of used materials.
magnetic nanoparticles. There are two opposite The term “formative biofabrication” was
opinions about the toxic effect of magnetic coined by Prof. Chua Chee Kai at the International
nanoparticles. One group of researchers, i.e., Bioprinting Congress in Singapore to describe
Claire Wilhelm’s group, is trying to demonstrate magnetic and acoustic levitational bioassembly
that superparamagnetic iron oxide nanoparticle is using magnetic and acoustic fields as desirable
practically not toxic and could be biodegraded to shape forming scaffold (personal communication).
natural ferritin . Moreover, a type of magnetic Formative biofabrication comprises the
[18]
nanoparticles-based contrast agent called technologies that uses magnetic, acoustic, electric,
“Feridex” has been used in clinical practice for photonic, and other physical forces for levitational
the decades. From another point of view, there is a bioassembly of 3D tissue and organ constructs.
growing number of researchers who demonstrate A new word “scaffield” has been proposed to
the toxic effect of magnetic nanoparticles and define magnetic and acoustic fields, which serve
claim that the accumulation of iron-based as some sort of temporal and removable support
magnetic nanoparticles could lead to undesirable for levitating and assembling biological objects.
side effects such as liver and spleen hemosiderosis Thus, formative biofabrication is a scaffold-
or the local accumulation of iron. free and label-free levitational bioassembly of
In a recently published review , the authors 3D tissues and organs that uses the combination
[19]
defined three main challenges for tissue engineering of different physical fields as removable temporal
based on removable physical fields (including support for levitating living building blocks which
Mag-TE): (i) Transition from academic-styled are capable of self-assembly. The device enabling
biofabrication of mini tissues to biofabrication of magnetic levitational bioassembly of 3D tissue and
clinically relevant tissue fragments; (ii) the use of organs should be called magnetic “bioassembler.”
more advanced materials; and (iii) development of Nowadays, there are no commercially available
affordable instrumentation. The current paper is magnetic levitational bioassemblers. Here, we
dealing with the third challenge – the production describe the first one of bioassemblers.
of bioassembler for magnetic levitational
bioassembly . 5 The main dilemma of label-free magnetic
[18]
levitational bioassembly
4 Concept of “scaffield” and “formative
biofabrication” Label-free magnetic levitational bioassembly
does not employ potentially toxic magnetic
There are three main ways of manufacturing: nanoparticles, which are often used in
(i) Subtractive, (ii) additive, and (iii) formative magnetic tissue engineering. Hence, label-free
manufacturing . During a long period from the magnetic levitational bioassembly may avoid the
[19]
early attempts until the end of the 20 century, problem of toxicity and associated undesirable
th
subtractive manufacturing was the primary way of potential side effect. However, the label-free
making things from wood, stones, and metals. At magnetic levitational bioassembly uses a
the end of the last century, additive manufacturing, paramagnetic medium, for example, a medium
initially known as the rapid prototyping technology, that contains gadolinium salts. Gadolinium salts
became a brilliant technology that formed the have already been approved for clinical imaging
technological basis of the so-called third or fourth as a contrast agent in computer tomography by
industrial revolution. Formative manufacturing the U.S. Food and Drug Administration and other

112 International Journal of Bioprinting (2020)–Volume 6, Issue 3