Reviewed by Lexie CornerJan 31 2025
Neurons form networks by exchanging signals, enabling learning and adaptation. Researchers at Delft University of Technology (TU Delft) have developed a 3D-printed neuronal culture platform that closely replicates brain tissue architecture. The study was published in Advanced Functional Materials and featured on its cover.
The researchers fabricated nanoscale pillar arrays to simulate the mechanical properties of neural tissue and the extracellular matrix. This model provides insights into neuronal network formation and may serve as a tool for studying alterations associated with neurological disorders such as Alzheimer’s, Parkinson’s, and autism spectrum disorders.
Neurons, like other cells, respond to the stiffness and structure of their environment. Traditional Petri dishes, being flat and rigid, do not replicate the soft, fibrous extracellular matrix of brain tissue. To address this, Associate Professor Angelo Accardo’s team designed nanopillar arrays using two-photon polymerization, a 3D laser-assisted printing technique with nanoscale precision.
The nanopillars, each thousands of times thinner than a human hair, are arranged in dense, forest-like patterns. By adjusting their aspect ratio (width-to-height ratio), the researchers controlled the effective shear modulus, a key mechanical property that influences cellular interactions within micro- and nano-structured environments.
This tricks the neurons into "thinking" that they are in a soft, brain-like environment, even though the nanopillars’ material itself is stiff. While bending under the crawling of neurons, the nanopillars not only simulate the softness of brain tissue but also provide a 3D nanometric structure that neurons can grab onto, much like the extra-cellular matrix nano-fibers in real brain tissue.
Angelo Accardo, Associate Professor, Delft University of Technology
This directly impacts how neurons develop and establish connections with one another.
From Random Growth to Ordered Networks
To evaluate the model, researchers cultured three types of neuronal cells, derived from mouse brain tissue or human stem cells, on the nanopillar arrays. Unlike the random growth observed on conventional flat Petri dishes and 2D biomaterials, neurons on the 3D-printed nanopillar structures exhibited organized growth, forming networks at specific angles.
The study also provided new insights into neuronal growth cone dynamics.
These hand-like structures guide the tips of growing neurons as they search for new connections. On flat surfaces, the growth cones spread out and remain relatively flat. But on the nanopillar arrays, the growth cones sent out long, finger-like projections, exploring their surroundings in all directions — not just along a flat plane but also in the 3D space, resembling what happens in a real brain environment.
Angelo Accardo, Associate Professor, Delft University of Technology
“In addition, we found that the environment created by the nanopillars also seemed to encourage neurons to mature,” highlights George Flamourakis, first author of the study. Neural progenitor cells cultured on the nanopillars exhibited increased levels of a marker associated with mature neurons compared to those grown on flat surfaces. “This shows that the system not only influences the direction of growth but also promotes neuronal maturation.”
A Tool for Studying Brain Disorders
If softness is so crucial, why not simply grow neurons on soft materials like gels?
The problem is that gel matrices, like collagen or Matrigel, typically suffer from batch-to-batch variability and do not feature rationally designed geometric features. The nanopillar arrays model offers the best of both worlds: it behaves like a soft environment with nanometric features, and holds extremely high reproducibility thanks to the resolution of two-photon polymerization.
Angelo Accardo, Associate Professor, Delft University of Technology
The research is a collaborative effort across three departments in the Faculty of Mechanical Engineering (PME, BmechE & DCSC), the Faculty of Applied Physics (ImPhys), and ErasmusMC, with support from the Mechanical Engineering Cohesion and NWO XS grants.
Journal Reference:
Flamourakis, G., et al. (2024). Deciphering the Influence of Effective Shear Modulus on Neuronal Network Directionality and Growth Cones’ Morphology via Laser‐Assisted 3D‐Printed Nanostructured Arrays. Advanced Functional Materials. doi.org/10.1002/adfm.202409451.