Diphenylalanine Peptide Nanowires as a Substrate for Neural Cultures

Abstract

Primary brain cells cultured on flat surfaces, i.e., in a two-dimensional fashion, have a long history of use as an experimental model system in neuroscience research. However, it is questionable to which extent these cultured brain cells resemble their in vivo counterparts. Mainly, it has been claimed that the non-oxidative glucose metabolism reflected by lactate production is unphysiologically high. Furthermore, it is known that culturing in 2D alters the phenotype of cells. Here we present diphenylalanine peptide nanowires (PNWs) as a culturing substrate for primary neocortical neurons from mice. The topology of the PNWs leads to neuronal cultures developing in 2.5D environment and hence improved culturing conditions. We investigate the effect of different concentrations of PNWs and different cell densities of neurons on the culturing conditions. The neocortical neurons were examined through scanning electron microscopy in order to study the effect of PNW concentrations and neuron densities on the structural appearance of the cells. Then employing the optimal combination of neuron density and PNW concentration, the neurons were evaluated functionally and metabolically by comparison with neocortical neurons standard culturing methods in 2D. Specifically, we tested neuronal viability, capacity for vesicular release of neurotransmitter GABA, as well as oxidative and non-oxidative glucose metabolism. It was evident that neurons cultured on PNWs exhibited increased viability combined with an increased capacity for neurotransmitter release and a lower fraction of non-oxidative metabolism than neurons cultured in 2D. Hence, neocortical neurons cultured in 2.5D on PNWs appear to be healthier and less glycolytic than neurons cultured in 2D.

Vertically Grown Bioinspired Diphenylalanine Nanowire-Coated Fabric for Oil–Water Separation

“…Due to their biocompatibility, the ability to readily self-assemble into nanowires or nanotubes in a solution or vapor environment, having robust mechanical properties, , and being piezoelectric due to inherently charged sites, these nanostructures of FF have found their application as substrates for cell cultures, material to increase surface roughness for supercapacitors, , template for conducting polymer nanotubes, and active material for piezoelectric energy harvesters. , Our work reported herein demonstrates yet another application of these FF nanowires as coatings for constructing oil–water separation membranes. The combination of high separation efficiency, extremely high oil flux, and long shelf-life demonstrates that bio-inspired FF nanowire-coated fabric-based hydrophobic mesh can be a robust, reliable, and low-cost alternative to commonly used methods for creating hydrophobic and oleophilic membranes for oil–water separation.…”

“…Due to their biocompatibility, the ability to readily selfassemble into nanowires or nanotubes in a solution 44 or vapor environment, 47 having robust mechanical properties, 42,43 and being piezoelectric due to inherently charged sites, 46 these nanostructures of FF have found their application as substrates for cell cultures, 49 material to increase surface roughness for supercapacitors, 61,62 template for conducting polymer nanotubes, 63 and active material for piezoelectric energy harvesters. 45,46 Our work reported herein demonstrates yet another application of these FF nanowires as coatings for constructing oil−water separation membranes.…”

“…FF is one of the most well-studied short peptides found as the core recognition motif of Alzheimer’s β-amyloid polypeptides. , Due to its aromaticity and charges, , FF can be self-assembled into rigid nanowires − by using solution-based − or vapor-based methods. − Using the alanine vapor-based deposition method, it was previously reported that the vertical growth of FF nanowires can result in hydrophobic surfaces. , In this paper, we report that the alanine vapor-based method can also be used to grow vertical FF nanowires on a fabric, which results in the formation of parahydrophobic and oleophilic fabric mesh. We also report that such a hydrophobic fabric can be used as a highly efficient (>99%) oil–water separating mesh with a long shelf-life without a significant degradation in the oil separation efficiency (>97%) even after a year.…”