Research Training Group 2154 - Materials for Brain

Project 6: Mishal Khan

Embedding implant materials into structured hydrogels

This second-generation project of RTG 2154 Materials for Brain, is highly interdisciplinary as it combines different aspects from chemistry, biophysics and materials science such as hydrogel synthesis and functionalization, mechanical properties of soft matter, as well as studies of cell migration and adhesion. 
With a shear modulus on the order of 1 kPa, brain is not only our softest, but also our least well-understood organ. Floating in the cerebrospinal fluid, embedded in the skull, it is almost perfectly isolated from its mechanical environment. The functional significance of implant material is dependent on the cellular reaction of the body towards the implant. Due to soft and hydrated environment of the brain it is essential to adapt the mechanical properties of implants to that of the surrounding tissue to avoid glial scar formation. Glial scars are thought to provide not only a biochemical but also a mechanical barrier to neuronal regeneration. The stiffness of the environment is indeed an important determinant of neuronal and glial cell growth and function. Unlike other soft tissues, the brain is not only ultra-soft, but also has an exceptionally high-water content. Material structure i.e., hydrogels, as this opens up many perspectives for controlling cell behavior and mimicking the natural extracellular environment, contains a lot of water, have a low modulus of elasticity and can be structured by template-based approaches and 3D printing. 
The aim of this research would primarily focus on synthesis and investigation of 3D porous, structured biocompatible hydrogels with a high-water content as coatings of brain implants and focus on their mechanics and stability i.e., preparation of certain stiffness-based hydrogels to match the mechanical behavior of the brain.  Another part would be to investigate forces, applied by the surrounding tissue and brain cells quantified by TFM (traction force microscopy) in the hydrogels, along with studies of cell migration and adhesion. A major part of this project which will focus on the hydrogel structure (structural, mechanical) to influence the formation of the glial scar in collaboration with project 7.