Patterned Substrates for the Study of Axonal Differentiation and Neuronal Response to Smooth Microtopography

Abstract

The development of two and three-dimensional patterned substrates provides new ways to study neuronal behavior. The creation of two-dimensional (2D) patterned surfaces through the use of photolithography, microcontact printing, and self-assembled monolayer (SAM) chemistry allows for the study of axonal differentiation. Through the use of these methods, we have created starburst patterns to which E18 mouse hippocampal neurons are confined. Utilizing immunohistochemistry to specifically stain for the tau protein, predominantly localized along microtubules in the axon, we have found that neurite differentiation is not a predetermined process; rather, it is environmentally determined. The compilation of statistical data has shown that a mere 20μm difference in the distance a neurite is allowed to grow will determine polarization.Grayscale photolithography and solvent-assisted molding (SAMo) allow us to create smooth microtopography that mimics the microtopography encountered in vivo. We have fabricated continuous three-dimensional (3D) wave patterns, varying height as well as the peak-to-peak distance, to the study of neuronal behavior in response to smooth variations in microenvironment. This will provide insights into the limitations a neuron may experience during pathfinding in vivo.