DIRECTING NEURONAL GROWTH IN 3D HYDROGELS

The ability to manipulate and direct neuronal growth has great importance in the field of tissue engineering, both for neuronal repair and potential medical devices. In-vivo, neurons grow and develop neurites in a 3-Dimensional (3D) extra cellular matrix (ECM) surrounding. Thus, imitating the 3D environment within a natural material as collagen is most important to simulate in-vivo conditions.

We designed and developed a method to grow neurons in a 3D hydrogel environment. We used both primary leech (Hirudo medicinalis) neuronal culture and, and followed the growth of single cells for up to 7 days.

We compared the neuronal growth in 3D to a 2D model and showed that neurons grown in 3D collagen gels develop significantly longer dendritic trees and neurites. To manipulate neuronal growth we developed a method to align collagen gel matrix via inducing strain on collagen gels. We showed fiber directionality by analysis of light microscope images via Fast Fourier transform and by SEM imaging. Finally, we evaluated leech neurite extension within aligned gels, via a designed Matlab script. Using aligned hydrogels we`ve directed neuronal growth coinciding with collagen matrix orientation. We also found aligned gels initiate neurite growth patterns similar to planner growth.

We further designed a magnetic hydrogel to direct neuronal growth in 3D. We have enriched the hydrogel neuronal culture with magnetic particles thus creating a magnetically responsive hydrogel. We analyzed neuronal growth in magnetically actuated hydrogels. Our results show directed neuronal growth in the modified hydrogels.