Increasing the sensitivity of microfluidics based immunoassays using isotachophoresis.

We have developed a microfluidic device that enhances the sensitivity of protein immunoassays by preconcentrating the protein sample using isotachophoresis (ITP). Two approaches were followed to study the sensitivity gain achieved that way. The first approach was using antibody-coated magnetic beads loaded into a microchannel to capture the proteins within the ITP sample zone.

Transport and separation of micron sized particles at isotachophoretic transition zones.

Conventionally, isotachophoresis (ITP) is used for separation of ionic samples according to their electrophoretic mobilities. We demonstrate that the scope of ITP applications may be extended toward particle concentration and separation. Owing to the distributions of electrolyte concentration and electric field inside a transition zone between two electrolytes, a number of different forces act on a small particle.

Micro contactor based on isotachophoretic sample transport.

It is demonstrated how isotachophoresis (ITP) in a microfluidic device may be utilized to bring two small sample volumes into contact in a well-controlled manner. The ITP contactor serves a similar purpose as micromixers that are designed to mix two species rapidly in a microfluidic channel. In contrast to many micromixers, the ITP contactor does not require complex channel architectures and allows a sample processing in the spirit of "digital microfluidics", i.