The article was originally published on 3ders.org

3D bioprinting is a process for patterning and assembling complex functional living architectures in a gradient fashion. Generally, 3D bioprinting utilizes the layer-by-layer method to deposit materials known as bioinks to create tissue-like structures. Several 3D bioprinting techniques have been developed over the last decade, for example, magnetic bioprinting, a method that employs biocompatible magnetic nanoparticles to print cells into 3D structures.

But now a Russian research team has developed a new method of bioprinting that allows to create 3D biological objects without the use of layer-by-layer approach and magnetic labels. The new method, which involves magnetic levitation research in conditions of microgravity, was conducted by the 3D Bioprinting Solutions company in collaboration with other Russian and foreign scientists, including the Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS).

A schematic image of an experimental setup with a "magnetic well" trap for holding bio-objects. Credit: Vladislav A Parfenov et al // Biofabrication, 2018

"During the period from 2010 to 2017, a series of unique experimental studies were carried out aboard the Russian Orbital Segment of the International Space Station at the experimental setup "Coulomb Crystal", said Mikhail Vasiliev, head of laboratory of dusty plasma diagnostics in JIHT RAS. "The main element of that device is an electromagnet that creates a special inhomogeneous magnetic field in which the structures of the diamagnetic particles (they are magnetized against the direction of the magnetic field) can be formed in the microgravity conditions."

In their experimental study, the researchers described how small charged particles behave in the magnetic field of a special shape under the microgravity or zero gravity conditions. In addition, the scientists developed a mathematical model of this process based on the methods of molecular dynamics. These results explain how to obtain homogeneous and extended three-dimensional structures consisting of the thousands of the particles.

Conventional methods of magnetic 3D bioprinting had a number of limitations associated with the gravity. To reduce the power of gravitational forces, one can increase the power of magnets that control the magnetic field. However, this will require a much more complex 3D bioprinter. The second way is to reduce the gravity, which is the approach used by the scientists from 3D Bioprinting Solutions. This method is called "formative three-dimensional biofactory" which allows you to create three-dimensional biological structures immediately from all the sides. The researchers applied the experimental data and the results of the mathematical modeling obtained by the JIHT RAS scientists to control the shape of such structures.

"The results of the Coulomb crystal experiment on the study of the formation of the spatially ordered structures led to the development of a new method for the formative 3D-biofactory of the tissue-like structures based on the programmable self-assembly of the living tissues and organs under the conditions of gravity and microgravity by means of an inhomogeneous magnetic field," said Vasiliev.

The process of 3D self-assembly in the "magnetic well". Credit: Vladislav A Parfenov et al // Biofabrication, 2018

Bioprinters based on this new technology will be able to create various biological constucts that can be used for many purposes, including estimating the adverse effects of space radiation on the health of astronauts on long-term space missions. In addition, it will also be able to restore the function of the damaged tissues and organs in the future.

Their paper, entitled “Scaffold-free, label-free and nozzle-free biofabrication technology using magnetic levitational assembly,” is published in Biofabrication.