The goal of this protocol is to describe the synthesis of two novel biocomposites with high-aspect ratio structures. The biocomposites consist of copper and cystine, with either copper nanoparticles (CNPs) or copper sulfate contributing the metallic component. Synthesis is carried out in liquid under biological conditions (37 °C) and the self-assembled composites form after 24 hr. Once formed, these composites are highly stable in both liquid media and in a dried form. The composites scale from the nano- to micro- range in length, and from a few microns to 25 nm in diameter. Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX) demonstrated that sulfur was present in the NP-derived linear structures, while it was absent from the starting CNP material, thus confirming cystine as the source of sulfur in the final nanocomposites. During synthesis of these linear nano- and micro-composites, a diverse range of lengths of structures is formed in the synthesis vessel. Sonication of the liquid mixture after synthesis was demonstrated to assist in controlling average size of the structures by diminishing the average length with increased time of sonication. Since the formed structures are highly stable, do not agglomerate, and are formed in liquid phase, centrifugation may also be used to assist in concentrating and segregating formed composites.
Glutamate (GLU) binding to neurons can cause dynamic changes in intracellular calcium. We tested effects of a 3-group submaximal glutamate stimulus (250, 500 and 750 nanomolar GLU in randomized orders) on neurons in culture, and measured intracellular calcium dynamics in cultures high and low in glia at 8 and 9 days in vitro. Gliadepleted cultures responded to increasing GLU with synchronized dynamics, leading to a greater "area under the curve" (AUC) for intracellular calcium over time. The AUC determined if the neuron would respond dynamically to the next addition of glutamate. This observation was not displayed within cultures high in glia, where AUC returned to baseline with every GLU addition, regardless of order of addition. Furthermore, the 3-group stimulus resulted in decreasing average AUC, regardless of order. In contrast, for cultures depleted of glia, the deciding factor of a responding cell to dynamically respond to GLU additions depended on the ability of the cell to distribute the calcium load (AUC) of the prior addition. Determining how neurons respond and behave such as in the presence of functional or dysfunctional glia, may help our understanding of signal processing in the brain.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.