Self-Aligned Functionalization Approach to Order Neuronal Networks at the Single-Cell Level

Abstract

Despite significant progress, our knowledge of the functioning of the central nervous system still remains scarce to date. A better understanding of its behavior, in either normal or diseased conditions, goes through an increased knowledge of basic mechanisms involved in neuronal function, including at the single-cell level. This has motivated significant efforts for the development of miniaturized sensing devices to monitor neuronal activity with high spatial and signal resolution. One of the main challenges remaining to be addressed in this domain is, however, the ability to create in vitro spatially ordered neuronal networks at low density with a precise control of the cell location to ensure proper monitoring of the activity of a defined set of neurons. Here, we present a novel self-aligned chemical functionalization method, based on a repellant surface with patterned attractive areas, which permits the elaboration of low-density neuronal network down to individual cells with a high control of the soma location and axonal growth. This approach is compatible with complementary metal-oxide-semiconductor line technology at a wafer scale and allows performing the cell culture on packaged chip outside microelectronics facilities. Rat cortical neurons were cultured on such patterned surfaces for over one month and displayed a very high degree of organization in large networks. Indeed, more than 90% of the network nodes were settled by a soma and 100% of the connecting lines were occupied by a neurite, with a very good selectivity (low parasitic cell connections). After optimization, networks composed of 75% of unicellular nodes were obtained, together with a control at the micron scale of the location of the somas. Finally, we demonstrated that the dendritic neuronal growth was guided by the surface functionalization, even when micrometer scale topologies were encountered and we succeeded to control the extension growth along one-dimensional-aligned nanostructures with sub-micrometrical scale precision. This novel approach now opens the way for precise monitoring of neuronal network activity at the single-cell level.

Robust Control of a Brain-Persisting Parasite through MHC I Presentation by Infected Neurons

“…An alteration of electrical properties has also been reported (Meuth et al, 2009). Future investigations should be undertaken to address whether cognate contacts between CTL and T. gondii-infected neurons could result in alterations of the electrical activity of individual neurons or integrated neuronal networks (Casanova et al, 2018). These experiments may ultimately shed light on some mechanisms behind the behavioral alterations induced by T. gondii.…”

Impact of Physical Obstacles on the Structural and Effective Connectivity of in silico Neuronal Circuits

“…We disregarded for simplicity the interaction of axons with neurons or with other axons, and used a simple “reflection” rule to model the interaction between axons and obstacles. In vitro experiments in engineered neuronal cultures (Feinerman et al, 2008 ; Li et al, 2014 ; Casanova et al, 2018 ) and microfluidic chambers (Renault et al, 2016 ; Yamada et al, 2016 ; Holloway et al, 2019 ) have shown that axons interact in complex ways with obstacles and that axons often attach to and follow walls. Thus, for a more realistic representation of in vitro behavior those interactions should be incorporated in future simulations.…”

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…Silanes, a collection of compounds based on different substituents of the silane molecule SiH 4 , are often used to promote the physisorption of biocargoes onto surfaces, [68,75,108,280] or to modify the wettability of the surface. [49,281] Silanes can include other reactive groups, making them a common coupling agent for joining biomaterials. [282] A common choice is (3-aminopropyl)triethoxysilane (often referred to by the acronym APTES).…”