Mesoscale magnetically-guided nanoparticle gradients generate spatially heterogeneous neuronal protein expression...

Spatial signal gradients are ubiquitous throughout in vivo tissues, with heterogeneous variables ranging from protein expression to tissue stiffness. Research into the development of biomimetic gradients has led to a wide range of technological advances within this field, with promise to progress tissue engineering for both therapeutic testing as well as tissue regeneration. However, most technologies are limited to the microscale or require complex tools and equipment to generate in vitro gradients. Here, we propose a low-cost method for generating in vitro meso-scale protein expression gradients using a 3D printed magnetic ring that exerted a spatially heterogeneous magnetic field within a standard 35-mm cell culture dish. We then optimized a method for magnetically guiding viral vectors for localized gene expression enrichment. Finally, we examine the potential for utilizing this platform to generate localized neuronal Ca²⁺ activity alterations.