Bachelor of Engineering, South China University Of Technology (2009)
Doctor of Philosophy, Zhejiang University (2014)
Utkan Demirci, Postdoctoral Faculty Sponsor
3-D geometry and irregular connectivity dictate neuronal firing in frequency domain and synchronization.
2019; 197: 171–81
The replication of the complex structure and three dimensional (3-D) interconnectivity of neurons in the brain is a great challenge. A few 3-D neuronal patterning approaches have been developed to mimic the cell distribution in the brain but none have demonstrated the relationship between 3-D neuron patterning and network connectivity. Here, we used photolithographic crosslinking to fabricate in vitro 3-D neuronal structures with distinct sizes, shapes or interconnectivities, i.e., milli-blocks, micro-stripes, separated micro-blocks and connected micro-blocks, which have spatial confinement from "Z" dimension to "XYZ" dimension. During a 4-week culture period, the 3-D neuronal system has shown high cell viability, axonal, dendritic, synaptic growth and neural network activity of cortical neurons. We further studied the calcium oscillation of neurons in different 3-D patterns and used signal processing both in Fast Fourier Transform (FFT) and time domain (TD) to model the fluorescent signal variation. We observed that the firing frequency decreased as the spatial confinement in 3-D system increased. Besides, the neuronal synchronization significantly decreased by irregularly connecting micro-blocks, indicating that network connectivity can be adjusted by changing the linking conditions of 3-D gels. Earlier works showed the importance of 3-D culture over 2-D in terms of cell growth. Here, we showed that not only 3-D geometry over 2-D culture matters, but also the spatial organization of cells in 3-D dictates the neuronal firing frequency and synchronicity.
View details for DOI 10.1016/j.biomaterials.2019.01.017
View details for PubMedID 30660993
- Biochemical Gradients to Generate 3D Heterotypic-Like Tissues with Isotropic and Anisotropic Architectures ADVANCED FUNCTIONAL MATERIALS 2018; 28 (48)
Tunable anisotropic networks for 3-D oriented neural tissue models.
2018; 181: 402–14
Organized networks are common in nature showing specific tissue micro-architecture, where cells can be found isotropically or anisotropically distributed in characteristic arrangements and tissue stiffness. However, when addressing an in vitro tissue model, it is challenging to grant control over mechanical properties while achieving anisotropic porosity of polymeric networks, especially in three-dimensional systems (3-D). While progress was achieved organizing cells in two-dimension (2-D), fabrication methods for aligned networks in 3-D are limited. Here, we describe the use of a biomimetic extra-cellular matrix system allowing programming of anisotropic structures into precisely advancing pore diameters in 3-D. Using control over polymeric composition, crosslinking directionality and freezing gradient dynamics, we revealed a mechanism to top-down biofabricate 3-D structures with tunable micro-porosity capable of directing cellular responses at millimeter scale such as axonal anisotropic outgrowth that is a unique characteristic of the brain cortex. Further, we showed the unique integration of this method with a microfluidic system establishing a neural-endothelial heterotypic conjugation, which can potentially be broadly applied to multiple organ systems.
View details for DOI 10.1016/j.biomaterials.2018.07.055
View details for PubMedID 30138793
- Regulating Growth Cone Motility and Axon Growth by Manipulating Targeted Superparamagnetic Nanoparticles USE OF NANOPARTICLES IN NEUROSCIENCE 2018; 135: 89–108