ABSTRACT
Multicolor electrophosphorescent organic light-emitting diode (OLED) pixel patterning by organic vapor jet printing (OVJP) is demonstrated, showing that this technique is capable of rapidly generating high-definition full-color displays. The resolution limits, and means to achieve them are described using a combination of simulation and experimental approaches.
ABSTRACT
Efficient and robust particle separation and enrichment techniques are critical for a diverse range of lab-on-a-chip analytical devices including pathogen detection, sample preparation, high-throughput particle sorting, and biomedical diagnostics. Previously, using insulator-based dielectrophoresis (iDEP) in microfluidic glass devices, we demonstrated simultaneous particle separation and concentration of various biological organisms, polymer microbeads, and viruses. As an alternative to glass, we evaluate the performance of similar iDEP structures produced in polymer-based microfluidic devices. There are numerous processing and operational advantages that motivate our transition to polymers such as the availability of numerous innate chemical compositions for tailoring performance, mechanical robustness, economy of scale, and ease of thermoforming and mass manufacturing. The polymer chips we have evaluated are fabricated through an injection molding process of the commercially available cyclic olefin copolymer Zeonor 1060R. This publication is the first to demonstrate insulator-based dielectrophoretic biological particle differentiation in a polymeric device injection molded from a silicon master. The results demonstrate that the polymer devices achieve the same performance metrics as glass devices. We also demonstrate an effective means of enhancing performance of these microsystems in terms of system power demand through the use of a dynamic surface coating. We demonstrate that the commercially available nonionic block copolymer surfactant, Pluronic F127, has a strong interaction with the cyclic olefin copolymer at very low concentrations, positively impacting performance by decreasing the electric field necessary to achieve particle trapping by an order of magnitude. The presence of this dynamic surface coating, therefore, lowers the power required to operate such devices and minimizes Joule heating. The results of this study demonstrate that iDEP polymeric microfluidic devices with surfactant coatings provide an affordable engineering strategy for selective particle enrichment and sorting.
Subject(s)
Biocompatible Materials/chemistry , Electrophoresis, Microchip , Microfluidics , Polymers/chemistry , Bacillus subtilis/metabolism , Bacillus thuringiensis/metabolism , Electrochemistry/methods , Equipment Design , Hot Temperature , Kinetics , Microfluidic Analytical Techniques , Poloxamer/chemistry , Surface Properties , Surface-Active Agents , Tissue Engineering/methodsABSTRACT
An analytical model is presented for the three-dimensional flow in the recently introduced staggered herringbone mixer for microchannels. In this model, the flow in the cross-section of the channel is treated as a lid-driven cavity flow. The model is shown to reproduce the advection patterns that were observed experimentally in the staggered herringbone mixer. The model is then used to study the quality of mixing in this flow as a function of geometry. Analysis is performed with Poincaré maps, mixing simulations, and residence time distributions. A range of optimal geometries is identified.
