In many tissues of the human body, such as nerve tissue, the spatial organization of cells plays an important role. Nerve cells and their long protrusions assemble into nerve tracts and transport information throughout the body. When such a tissue is injured, an accurate spatial orientation of the cells facilitates the healing process. In Anisogel, we developed an injectable gel, which can act as a guidance system for nerve cells. Inside the body, an extracellular matrix surrounds the cells. It provides mechanical support and promotes spatial tissue organization. In order to regenerate damaged tissue, an artificial matrix can temporally replace the natural extracellular matrix. This matrix needs to mimic the natural cell environment in order to efficiently stimulate the regenerative potential of the surrounding tissue. Solid implants, however, may impair remaining healthy tissue whereas soft, injectable materials allow for a minimal invasive therapy, which is particularly beneficial for sensitive tissues, such as the spinal cord. Unfortunately, up to now, artificial soft materials did not yet reproduce the complex structures and spatial properties of natural tissues.
The newly developed minimal invasive material is termed ‚Anisogel‘. If you aim to enhance the regeneration of damaged spinal cord tissue, you need to come up with a new material concept. We use micrometer-sized building blocks and assemble them into 3D hierarchically organized structures. Anisogel consists of two gel components. Many, microscopically small, soft rod-shaped gels, incorporated with a low amount of magnetic nanoparticles, are the first component. Using a weak magnetic field, scientists can orient the gel rods, after which a very soft surrounding gel matrix is crosslinked, forming the structural guidance system. The gel rods, being stabilized by the gel matrix, maintain their orientation, even after removal of the magnetic field. Using cell culture experiments, we demonstrate that cells can easily migrate through this gel matrix, and that nerve cells and fibroblasts orient along the paths provided by this guidance system. A low amount of one percent gel rods inside the entire Anisogel volume is proven to be sufficient to induce linear nerve growth. The material is the first injectable biomaterial, which assembles into a controlled oriented structure after injection and provides a functional guidance system for cells.
