Networks of neuroblastoma cells on porous silicon substrates reveal a small world topology

Abstract

The human brain is a tightly interweaving network of neural cells where the complexity of the network is given by the large number of its constituents and its architecture. The topological structure of neurons in the brain translates into its increased computational capabilities, low energy consumption, and nondeterministic functions, which differentiate human behavior from artificial computational schemes. In this manuscript, we fabricated porous silicon chips with a small pore size ranging from 8 to 75 nm and large fractal dimensions up to Df ∼ 2.8. In culturing neuroblastoma N2A cells on the described substrates, we found that those cells adhere more firmly to and proliferate on the porous surfaces compared to the conventional nominally flat silicon substrates, which were used as controls. More importantly, we observed that N2A cells on the porous substrates create highly clustered, small world topology patterns. We conjecture that neurons with a similar architecture may elaborate information more efficiently than in random or regular grids. Moreover, we hypothesize that systems of neurons on nano-scale geometry evolve in time to form networks in which the propagation of information is maximized.

Cortical-like mini-columns of neuronal cells on zinc oxide nanowire surfaces

“…Nano-topography is especially important in guiding cell fate at the bio-interface, and is therefore of interest in neural tissue engineering, bio computing, biosensors operations and neural cell based sensors, the diagnosis and analysis of neurodegenerative disorders, neural development [44][45][46] . In previously reported studies 39,47,48 , we examined patterns of neuroblastoma N2A cells on meso-porous silicon. We observed that N2A cells on a surface with nano-scale motifs display an increased ability to create patterns in which the nodes of the patterns form highly clustered groups and the elements of the groups are connected by a finite, and generally low, number of steps.…”

Surface enhanced Raman spectroscopy measurements of MCF7 cells adhesion in confined micro-environments

“…Since the flat surface is isotropic for the cells, they are free to express their own normal profile and topography. Instead the two cells on the pillars grow on an anisotropic 3D surface, and during development they adapt themselves to the surrounding environment [52,53]. More in details, as the cells becomes larger than the top size of the pillar, they are forced to find the closest anchorage point to avoid growth on the sidewall of the pillar.…”

Relating the small world coefficient to the entropy of 2D networks and applications in neuromorphic engineering

“…From the distributions of points in the plane we determined the corresponding graphs by connecting nodes by a wiring algorithm. We used the Waxman model (Waxman, 1988, Marinaro et al 2015, whereby the probability of being a link between two nodes exponentially decreases with the Euclidean distance between those nodes. For a given set of two nodes u and v, the link probability, P u v , ( )is defined as:…”

“…In other reported studies (Takahashi et al 2010), it has been demonstrated that the functional and anatomical connectivity among individual neurons exhibits small-world architectures. In references (Marinaro et al 2015, Onesto et al 2017, some of the authors of the present paper used surfaces with controlled nanotopography to guide the organization of neuronal cells into small world networks with enhanced information flows. Using experiments, information theory approaches and network analysis, we have demonstrated that the formation of the fundamental computation units of the nervous system (such as cortical mini-columns in the cerebral cortex) is guided by the interplay between energy minimization, information optimization and topology.…”