Microfluidic platforms that physically guide axons enable controlled studies of neuronal connectivity, injury, and regeneration in vitro. This thesis investigates two fabrication routes for Polydimethylsiloxane (PDMS)-based axon-guidance structures: direct ink writing of printable PDMS inks and cleanroom microfabrication using photolithography and DRIE, with the goal of achieving high-aspect-ratio and high-density features suitable for neuronal applications. Printable PDMS inks were formulated by blending shear-thinning SE1700 with Sylgard 184 at varying ratios and characterized by shear viscosity and oscillatory rheology at 25 °C. SE1700-containing blends exhibited pronounced shear thinning and gel-like behavior (G′ > G″) in the linear viscoelastic regime. DIW printability was assessed via dual-layer tests and filament-width analysis under different nozzle sizes, speeds, and displacements. The 8:2 ink provided the best balance between extrusion and shape retention; however, multilayer pores still showed sagging or merging depending on overhang span and dose, and dimensional errors on printed microchannels ranged from 32 to 157 µm depending on geometry. Additionally, microfabrication produced high-aspect-ratio features on silicon using positive and negative routes. PDMS–PDMS double casting from positive molds revealed failure modes—lateral collapse and longitudinal tearing, in dense, narrow structures during demolding. Direct PDMS casting from negative silicon molds improved geometric fidelity and avoided tearing; measured aspect ratio is close to the wafer values and spontaneous collapse was not observed after demolding. Overall, DIW enables fast, mold-free prototyping but is limited in resolution and multilayer fidelity; microfabrication delivers micron-precision HAR arrays but entails higher process complexity and demolding risks for dense features. The results outline practical design and process for building PDMS platforms that can be further integrated with MEAs for functional neural studies.