We present a highly parallel microfluidic approach for contacting single cell pairs. The approach combines a differential fluidic resistance trapping method with a novel cellular valving principle for homotypic and heterotypic single cell co-culturing. Differential fluidic resistance was used for sequential single cell arraying, with the adhesion and flattening of viable cells within the microstructured environment acting to produce valves in the open state. Reversal of the flow was used for the sequential single cell arraying of the second cell type. Plasma stencilling, along the linear path of least resistance, was required to confine the cells within the trap regions. Prime flow conditions with minimal shear stress were identified for highly efficient cell arraying (∼99%) and long term cell culture. Larger trap dimensions enabled the highest levels of cell pairing (∼70%). The single cell co-cultures were in close proximity for the formation of connexon structures and the study of contact modes of communication. The research further highlights the possibility of using the natural behaviour of cells as the working principle behind responsive microfluidic elements.

The present review reflects the importance of dielectric barrier discharges in analytical chemistry. Special about this discharge is—and in contrast to usual discharges with direct current—that the plasma is separated from one or two electrodes by a dielectric barrier. This gives rise to two main features of the dielectric barrier discharges; it can serve as dissociation and excitation device and as ionization mechanism, respectively. The article portrays the various application fields for dielectric barrier discharges in analytical chemistry, for example the use for elemental detection with optical spectrometry or as ionization source for mass spectrometry. Besides the introduction of different kinds of dielectric barrier discharges used for analytical chemistry from the literature, a clear and concise classification of dielectric barrier discharges into capacitively coupled discharges is provided followed by an overview about the characteristics of a dielectric barrier discharge concerning discharge properties and the ignition mechanism.

We present a rapid, reproducible and sensitive neurotoxicity testing platform that combines the benefits of neurite outgrowth analysis with cell patterning. This approach involves patterning neuronal cells within a hexagonal array to standardize the distance between neighbouring cellular nodes, and thereby standardize the length of the neurite interconnections. This feature coupled with defined assay coordinates provides a streamlined display for rapid and sensitive analysis. We have termed this the network formation assay (NFA). To demonstrate the assay we have used a novel cell patterning technique involving thin film poly(dimethylsiloxane) (PDMS) microcontact printing. Differentiated human SH-SY5Y neuroblastoma cells colonized the array with high efficiency, reliably producing pattern occupancies above 70%. The neuronal array surface supported neurite outgrowth, resulting in the formation of an interconnected neuronal network. Exposure to acrylamide, a neurotoxic reference compound, inhibited network formation. A dose–response curve from the NFA was used to determine a 20% network inhibition (NI₂₀) value of 260 µM. This concentration was approximately 10-fold lower than the value produced by a routine cell viability assay, and demonstrates that the NFA can distinguish network formation inhibitory effects from gross cytotoxic effects. Inhibition of the mitogen-activated protein kinase (MAPK) ERK1/2 and phosphoinositide-3-kinase (PI-3K) signaling pathways also produced a dose-dependent reduction in network formation at non-cytotoxic concentrations. To further refine the assay a simulation was developed to manage the impact of pattern occupancy variations on network formation probability. Together these developments and demonstrations highlight the potential of the NFA to meet the demands of high-throughput applications in neurotoxicology and neurodevelopmental biology.