Effect of substrate wettability in liquid dielectrophoresis (LDEP) based droplet generation: theoretical analysis and experimental confirmation.

The generation of droplets for biological reactions at the microscale can be achieved by many techniques, among which the so-called liquid dielectrophoresis technique (LDEP). This is not a new process, but the parameters influencing actuation voltage still need further insight: size and geometry (electrodes width and gap, dielectric thickness), materials (dielectric constant), liquids (surface tension, dielectric constant, conductivity), working conditions (voltage, frequency) and substrate wettability (contact angle). This large experimental space is firstly reduced using non dimensional numbers and then studied in a systematic way thanks to the design of experiments. The contact angle influence is explained thanks to a new analytical model. To summarize, this paper recalls analytical models used to predict the voltage threshold required to develop a liquid rivulet from a mother drop, taking the contact angle into account and providing a large set of experimental results.

Characterization of DNA bio-bonds for meso-scale self-assembly.

In this paper, we have investigated the use of DNA hybridization as the basis for the production of new mesoscale components. AFM experimental results are studied and compared to two theoretical approaches: molecular and thermodynamic. We explain how and why DNA hybridization process can provide a good bond to self assemble components, and how molecular modelling methods allow further understanding of the physical mechanism of this process. Furthermore, the strength interaction of DNA complementary strands is measured and analyzed using statistical tools. These results are then compared to the theoretical approaches.