This paper describes a device in which the DEP electrodes form the channel walls. This is achieved by fabricating microfluidic channel walls from highly doped silicon so that they can also function as DEP electrodes. The device is fully enclosed and there is no fluidic leakage due to lead-outs. The electrode arrangement minimized the electrical dead volumes such that the DEP force is always sufficient to overcome Stoke's force and concentrate the cells and beads at the nominal operating potential of 25 Vp–p. The device has been tested successfully with yeast cells. When the actuation signal was increased to 13 Vp–p, cells began to move towards the tip of the DEP electrodes, where the electric field gradient was highest. As the actuation voltage increased, the cells moved faster. For 25 Vp–p, a stable equilibrium of cell concentration pattern was achieved in 10–13 s.

The reactions between arylethynes (either BuLi activated or Et3N assisted) and Ru2(RDMBA)4X2, where RDMBA is either N,N ‘-dimethylbenzamidinate (R = H) or N,N ‘-dimethyl-m-methoxybenzamidinate (R = m-MeO) and X is either Cl- or NO3 -, resulted in the compounds Ru2(RDMBA)4(C⋮CC6H4Y)2 (Y = H (1a,b), 4-NO2 (2a,b), 4-CN (3a,b), 3-CN (4a,b), 4-NMe2 (5a,b); R = H (a), m-MeO (b)). The single-crystal X-ray diffraction study of 1b and 2a revealed the linear alignment of the arylethynyl ligands along the Ru−Ru vector. All of the compounds display two Ru-based one-electron processes, an oxidation and a reduction, and their electrode potentials correlate linearly with the Hammett constants of substituent Y. Compounds 5a,b display an additional pair of one-electron processes attributed to the oxidation of 4-NMe2 groups, on the basis of which an extensive electron delocalization along the metallayne backbone was inferred.

A field-flow dielectrophoretic separation method in a 3D filtering chip has been developed in this work. The separation method was possible due to the special configuration of the DEP filtering chip, which has a structure similar to a classical capacitor with two parallel plate electrodes (realized by using a stainless steel mesh) and a dielectric medium (defined by a suspension of 100 µm diameter silica beads in buffer solution). The dielectrophoretic phenomenon is generated by the non-uniformities of the dielectric media, which produce a gradient of the electric field and, as a consequence, a DEP force. If a suspension medium with cells flows through the filter, the DEP force can trap these cells around the contact points between the silica beads (if the cells exhibit positive DEP) or they are repelled into the space between the beads (if the cells exhibit negative DEP). It is shown that for two different cell populations, the frequency of the electric field and permittivity of the media can be tuned in such a way that one population will exhibit positive DEP and the other one negative DEP. The population that expresses negative DEP can be easily flushed out due to the hydrodynamic force which is larger at the center point between the beads. In such a way two cell populations can be separated. The working principle was verified with both live and dead yeast cells. Best results for the separation of viable and nonviable cell populations were achieved at an applied voltage of 150 V in a frequency range between 10 kHz and 20 kHz for flow rates of 0.1 ml min −1 and 0.2 ml min −1 . With a few of these devices cascaded in series, higher efficiency could be achieved. As a result, this device and the associated proposed separation method can be very useful tools for bio-pharmaceutical industries since continuous flow separation at relatively high flow rates is both time and cost saving.

A new series of Ru2(DMBA)4(oligo(phenyleneethyne))2 compounds bearing sulfide termini was synthesized; structural characterization revealed both the rigid rod nature and extended pi-conjugation in these metallaynes; in the presence of these metallaynes, Au nanoparticles readily assembled into dimers and chains with well-defined inter-dimer distances.

A vascular-liver chip for sensitive detection of nutraceutical metabolites from human pluripotent stem cell derivatives