Neurite growth kinetics regulation through hydrostatic pressure in a novel triangle-shaped neurofluidic system

Abstract

Microfluidic neuro-engineering design rules have been widely explored to create in vitro neural networks with the objective to replicate physiologically relevant structures of the brain. Several neurofluidic strategies have been reported to study the connectivity of neurons, either within a population or between two separated populations, through the control of the directionality of their neuronal projections. Yet, the in vitro regulation of the growth kinetics of those projections remains challenging. Here, we describe a new neurofluidic chip with a triangular design that allows the accurate monitoring of neurite growth kinetics in a neuronal culture. This device permits to measure the maximum achievable length of projecting neurites over time and to report variations in neurite length under several conditions. Our results show that, by applying positive or negative hydrostatic pressure to primary rat hippocampal neurons, neurite growth kinetics can be tuned. This work presents a pioneering approach for the precise characterization of neurite length dynamics within an in vitro minimalistic environment.

Modeling Neurodegenerative Diseases Using In Vitro Compartmentalized Microfluidic Devices

“…The original design can be adapted for other applications. For example, Maisonneuve et al (2021a) have manufactured a novel triangle-shaped neurofluidic device to study the kinetics of neurite growth (Table 1, 2nodes). Both channels were linked by asymmetric microchannel of various length allowing the accurate monitoring of neurite growth kinetics in a neuronal culture.…”

“…The functional communication among neurons within a circuit through axonal transmission is a biological process difficult to monitor with classical non-compartmentalized neuronal cultures (Park et al, 2013b;Choi et al, 2017;Osaki et al, 2018a). Neuronal network analysis is possible within microfluidic systems (Maisonneuve et al, 2021a). They thus allow the monitoring of both structural and functional aspects of neuronal culture, making possible to study the impact of a compound applied in one compartment, whose effects are observed in the others (Johnstone et al, 2010;Delamarche et al, 2013).…”

“…They have shown a direct connectivity and network communication across a five-population neuronal circuit (Figure 2C). In another study, Maisonneuve et al (2021a) used neurofluidic technology to create a model of the direct way of BG loop of the brain, involved in Parkinson disease and Huntington disease, composed of five interconnected compartments. Each nodes represented an anatomical region involved in BG loop and were aligned on the device with respect to the cell number ratios between the various brain regions, linked with microchannel (Table 1) (Maisonneuve et al, 2021b).…”

Deposition chamber technology as building blocks for a standardized brain-on-chip framework

“…Based on the already mentioned structural configuration of our microfluidic design, none of the devices presented in this work require the use of pumping systems, in comparison to previously published microfluidic approaches 19,21,[26][27][28][29] . As an alternative to such systems, we exploit the difference in hydrostatic pressure between the inlet and outlet reservoirs to generate a controlled fluid flow.…”