We are increasingly encountering 3D printing in the medical field for the production of organs. For example, in the case of the researchers at the University of Wisconsin-Madison, who produced the first functional 3D printed human brain tissue. Now there has been yet another example, as Viennese researchers have developed what they claim to be the world’s first high-resolution 3D-printed brain phantom. The researchers hope it will be useful for further research into neurodegenerative diseases such as Alzheimer’s, Parkinson’s and multiple sclerosis as well as for planning operations.
The breakthrough was achieved as part of a collaboration between the Medical University of Vienna (MedUni Vienna) and Vienna University of Technology (TU Wien). The model of the 3D printed brain, which the scientists also call a “brain phantom”, hardly resembles a real brain visually, as it is shaped in a cube and is significantly smaller. Inside, however, the model contains tiny water-filled microchannels that mimic cranial nerves and are only a fifth of the size of a human hair.
Photo Credits: MedUni Vienna
The purpose of the model is to imitate the structure of brain nerve fibers and to visualize them using diffusion-weighted magnetic resonance imaging (dMRI), a special form of MRI. MRI is used in particular to examine the structure and function of the brain, and dMRI can even be used to identify the direction of nerve fibers in the brain. The 3D-printed brain phantom will now help to optimize the dMRI procedure and test analysis and evaluation methods. This should prove useful, as the direction of the nerve fibers has been very difficult to determine up to now, due to the fact that nerve fibers moving in different directions overlap at crossing points of nerve fiber bundles.
Using 3D Printing to Make a Brain Phantom
3D printing has many advantages for the production of this ‘brain phantom’, as it can be used to create complex and diverse designs in a flexible manner that can undergo repeated design iterations for adaptation and modification. 3D-printed brain phantoms are therefore also able to represent the complex overlapping nerve fibers in the brain. The model is examined by dMRI in the same way as a real brain and the data analyzed.
The model also has the advantage that the printed structure is known and the results of the dMRI analysis can therefore be verified, as the study showed. Thanks to 3D-printed brain phantoms with their realistic imitation of the structure of the nerve fibers, the analysis software of the dMRI can therefore be improved.
To 3D print the structures of the nerve fibers, the researchers used two-photon polymerization (2PP), which is often used for the additive manufacturing of microstructures in the nanometer and micrometer range. The researchers scaled up the 2PP process in order to obtain brain phantoms with high-resolution details suitable for dMRI.
One of the lead authors of the study from the Center for Medical Physics and Biomedical Engineering at MedUni Vienna, Michael Woletz, further explained, “We see the greatest progress in photography with mobile phone cameras not necessarily in new, better lenses, but in the software that improves the captured images. The situation is similar with dMRI: using the newly developed brain phantom, we can adjust the analysis software much more precisely and thus improve the quality of the measured data and reconstruct the neural architecture of the brain more accurately.”
The phantom designs and validation (photo credits: Woletz et al.)
However, there are still hurdles for the researchers to overcome in terms of scaling up the method, according to Franziska Chalupa-Gantner, the second lead author of the study from the Printing and Biofabrication research group at TU Wien, “The high resolution of two-photon polymerization makes it possible to print details in the micro- and nanometer range and is therefore very suitable for imaging cranial nerves. At the same time, however, it takes a correspondingly long time to print a cube several cubic centimeters in size using this technique. We are therefore not only aiming to develop even more complex designs, but also to further optimize the printing process itself.” For further information, you can find the research paper HERE.
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*Cover Photo Credits: MT Portal