Pico-force optical exchange (pico-FOX): utilizing optical forces applied to an orthogonal electroosmotic flow for particulate enrichment from mixed sample streams.

Results are reported from a combined optical force and electrokinetic microfluidic device that separates individual particulates from molecular components in a mixed sample stream. A pico-Newton optical force was applied to an orthogonal electroosmotic flow carrying a hydrodynamically pinched, mixed sample, resulting in the separation of the various particles from the sample stream. Different combinations of polystyrene, PMMA, and silica particles with a commercially available dye were utilized to test the different separation modes available, from purely optical force to combined optical and electrophoretic forces.

Orthogonal optical force separation simulation of particle and molecular species mixtures under direct current electroosmotic driven flow for applications in biological sample preparation.

Presented here are the results from numerical simulations applying optical forces orthogonally to electroosmotically induced flow containing both molecular species and particles. Simulations were conducted using COMSOL v4.2a Multiphysics® software including the particle tracking module.

Identifying indoor environmental patterns from bioaerosol material using HPLC.

A substantial portion of the atmospheric particle budget is of biological origin (human and animal dander, plant and insect debris, etc.). These bioaerosols can be considered information-rich packets of biochemical data specific to the organism of origin.

Manipulation and capture of Aβ amyloid fibrils and monomers by DC insulator gradient dielectrophoresis (DC-iGDEP).

Here we report a novel method for the manipulation and concentration of Aβ amyloid fibrils, implicated in Alzheimer's disease, using DC insulating gradient dielectrophoresis (DC-iGDEP). Fibril enrichment was found to be ∼400%. Simulations suggest that capture of the full range of amyloid protein aggregates is possible with optimized device design.

Exploring the feasibility of bioaerosol analysis as a novel fingerprinting technique.

The purpose of this review is to investigate the feasibility of bioaerosol fingerprinting based on current understanding of cellular debris (with emphasis on human-emitted particulates) in aerosols and arguments regarding sampling, sensitivity, separations, and detection schemes. Target aerosol particles include cellular material and proteins emitted by humans, animals, and plants and can be regarded as information-rich packets that carry biochemical information specific to the living organisms present where the sample is collected. In this work we discuss sampling and analysis techniques that can be integrated with molecular (e.

Blood cell capture in a sawtooth dielectrophoretic microchannel.

Biological fluids can be considered to contain information-rich mixtures of biochemicals and particles that enable clinicians to accurately diagnose a wide range of pathologies. Rapid and inexpensive analysis of blood and other bodily fluids is a topic gaining substantial attention in both science and medicine. One line of development involves microfluidic approaches that provide unique advantages over entrenched technologies, including rapid analysis times, microliter sample and reagent volumes, potentially low cost, and practical portability.

Characterization of particle capture in a sawtooth patterned insulating electrokinetic microfluidic device.

Here we present a scheme to separate particles according to their characteristic physical properties, including size, charge, polarizability, deformability, surface charge mobility, dielectric features, and local capacitance. Separation is accomplished using a microdevice based on direct current insulator gradient dielectrophoresis that can isolate and concentrate multiple analytes simultaneously at different positions. The device is dependent upon dielectrophoretic and electrokinetic forces incorporating a global longitudinal direct current field as well as using shaped insulating features within the channel to induce local gradients.

Insulator-based dielectrophoretic separation of small particles in a sawtooth channel.

Insulator-based dielectrophoretic separation of small particles in a sawtooth channel is studied in the limit of dilute concentration. Pathlines for the movements of infinitesimal particles are constructed and the geometric changes of these pathlines are used to establish the criterion for blocking and trapping particles with different physical properties. The sharp corners of the sawtooth channel create much stronger dielectrophoretic force than channels with smooth corners for blocking particle movements.

Bioanalytical separations using electric field gradient techniques.

The field of separations science will be strongly impacted by new electric-field-gradient-based strategies. Many new capabilities are being developed with analytical targets ranging from particles to small molecules, and soot to living cells. Here we review the emerging area of electric field gradient techniques, dividing the large variety of techniques by the target of separation.

Uptake and dissolution of gaseous ethanol in sulfuric acid.

The solubility of gas-phase ethanol (ethyl alcohol, CH3CH2OH, EtOH) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (209-237 K) and acid composition (39-76 wt % H2SO4). Ethanol is very soluble under these conditions: effective Henry's law coefficients, H, range from 4 x 10(4) M atm(-1) in the 227 K, 39 wt % acid to greater than 10(7) M atm(-1) in the 76 wt % acid. In 76 wt % sulfuric acid, ethanol solubility exceeds that which can be precisely determined using the Knudsen cell technique but falls in the range of 10(7)-10(10) M atm(-1).