Magnetohydrodynamic microfluidic systems including modified electrodes and methods of using the same

A magnetohydrodynamic microfluidic system and a method of pumping a fluid using a magnetohydrodynamic system are disclosed. The method includes applying at least one of an electric current and an electric voltage to a first modified electrode and a second electrode to generate an ionic current between the first modified electrode and the second electrode and to cause a current carrying species to move to or from the modified electrode, applying a magnetic field perpendicular to an ionic current vector, the magnetic field and the ionic current combining to induce flow of the fluid in a direction perpendicular to the magnetic field and the ionic current vector, and maintaining fluid flow by recharging the modified electrode

Microvolume immunoabsorbant assays with amplified electrochemical detection

Describes a structure and method for chemical sensing utilizing microassays. Microcavities or micropores are combined with assay techniques to provide a very fast and very sensitive means of detecting chemical compounds. Assay techniques are modified to include a metal ion binding carrier species especially suitable for use in conjunction with the electrochemical detection. This allows assays to be combined with electrochemical analysis, thus allowing the high speed ease and hypersensitivity available in the invention

Electrochemistry using permanent magnets with electrodes embedded therein

Devices and methods of enhancing mass transport proximate a surface of an electrode immersed in a liquid are disclosed. One aspect of the device comprises an electrode embedded in a sintered or bonded magnetic material. The device is contacted with a solvent containing a redox material dissolved therein. An external voltage or current is applied to the electrode which external voltage or current is sufficient to enhance mass transport proximate the surface of the electrode. Magnetic field effects can be effectively applied to the microstirring of fluids in conjunction with microelectrochemical systems in a lab-on-a-chip format. Suitable applications include bioassays, drug discovery, and high throughput screening, and other applications where magnetohydrodynamics can enhance chemical detection and/or reagent mixing which otherwise rely on diffusional processes

Combining magnetic forces for contactless manipulation of fluids in microelectrode-microfluidic systems

A novel method to drive and manipulate fluid in a contactless way in a microelectrode-microfluidic system is demonstrated by combining the Lorentz and magnetic field gradient forces. The method is based on the redox-reaction [Fe(CN)6]3−/[Fe(CN)6]4− performed in a magnetic field oriented perpendicular to the ionic current that crosses the gap between two arrays of oppositely polarized microelectrodes, generating a magnetohydrodynamic flow. Additionally, a movable magnetized CoFe micro-strip is placed at different positions beneath the gap. In this region, the magnetic flux density is changed locally and a strong magnetic field gradient is formed. The redox-reaction changes the magnetic susceptibility of the electrolyte near the electrodes, and the resulting magnetic field gradient exerts a force on the fluid, which leads to a deflection of the Lorentz force-driven main flow. Particle Image Velocity measurements and numerical simulations demonstrate that by combining the two magnetic forces, the flow is not only redirected, but also a local change of concentration of paramagnetic species is realized

Microfluidics and small volume mixing based on redox magnetohydrodynamics methods

Microfluidic channels utilizing magnetohydrodynamics are used to pump very small volumes of solution. The channels have electrodes along the walls of the channel, and a current carrying species within the solution carries the current through the solution. The electric field generated by the use of the current carrying species is perpendicular to a magnetic field applied to the channel. The combination of the electric and magnetic fields causes the solution to flow through the channel

Self-contained microelectrochemical bioassay platforms and methods

Describes methods and devices for improved chemical and biomass detection assays that combine well defined microstructures having independently addressable electrodes with various surface immobilization electrochemical assays. Combining known chemical detection immobilization assays, electrochemically active moieties with microstructures having independently addressable electrodes provides for vastly improved methods of detecting microorganisms, chemical compounds, and measuring membrane transport

Microfluidics and small volume mixing based on redox magnetohydrodynamics methods

Microfluidic channels utilizing magnetohydrodynamics are used to pump very small volumes of solution. The channels have electrodes along the walls of the channel and a current carrying species within the solution carries the current through the solution. The electric field generated by the use of the current carrying species is perpendicular to a magnetic field applied to the channel. The combination of the electric and magnetic fields causes the solution to flow through the channel

Self-contained microelectrochemical bioassay platforms and methods

The present invention relates to a microvolume electrochemical detection assay. More specifically, the present invention relates to microscale structures having an analyte immobilizing surface and at least one electrode separate from the immobilizing surface. The microscale devices are used in conjunction with an immobilization assay that utilizes an electroactive complex to generate a current that may be detected by the electrode. The small volumes and sensitivity of the assays used in conjunction with microstructures provides an extremely rapid detection method having superior sensitivity to existing methods

Electrochemical method for detecting water born pathogens

A novel surface immobilization electrochemical assay that allows for rapid, accurate and highly sensitive detection of microorganisms and biological molecules is described. Known surface immobilization methods are utilized to bind an analyte to a surface. A binding material with a covalently attached electroactive complex generates electrical current in the presence of analyte. An electrode is used to detect the current that is directly related to the concentration of analyte. The invention is especially suitable for detection of Cryptosporidium parvum

Microfabricated recessed disk microelectrodes: characterization in static and convective solutions

Construction and characterization of microfabricated recessed disk microelectrodes (RDMs) of 14 and 55 µm diameter are reported. Hybrid blamers were constructed by fusion of vesicles of dimyristoylphosphatidyl choline (DMPC), which forms the top layer, with ethanol-rinsed SAMs of hexadecanethiol on gold, which form the bottom layer. Gramicidin A was included in the modifying solutions to incorporate it into hybrid blamers