Photosensitive pattern to control geometry and activity of a neural network

A key challenge in neuroscience is understanding how a neural network's structure affects its activity. A simple and controllable environment like the in vitro neural network remains a powerful tool for studying physiological and pathological behaviors. Thanks to innovative printing techniques, the control of the biopolymer deposition are improved. Inkjet printing has gained much attention among patterning techniques because of its high resolution and direct-write approach, which enables the production of patterned substrates. Controlled deposition of an adhesion factor on the surface of the microelectrode array (MEA) makes it possible to guide the development of a neuronal network on a substrate that can record its activity, allowing the geometry of the network to be related to its activity. However, the inks commonly used can guide only the structure of a neural network, neglecting the functionality part. In this work, we synthesize a photosensitive ink that can be printed with a commercial inkjet printer, where thanks to its photothermal properties, we can modulate the neural activity. The photosensitive pattern printed on the MEA substrate allows a device to control the neural network geometry, record and modulate its activity. This work aims to provide an easy, versatile, fast and low-cost tool for studying the recurring relationship between the structure and function of neuronal networks.