Blood group typing by electrophoresis based on isoelectric focusing

Graphene-Enabled High-Performance Electrokinetic Focusing and Sensing

“…Development of micro-end-to-end analytical instrumentation remains a key challenge for advancing biotechnology and medical applications. − Isoelectric focusing is an electrokinetic method ideal to be implemented in microfluidic devices for bioanalysis (separation, concentration, and detection). − Conventional microisoelectric-focusing devices rely on a high voltage supply (>150 V) to generate pH gradients along the fluid-flow direction that is longitudinal to a capillary, thus incompatible to many microelectronics-based lab-on-a-chip technologies. , Alternatively, transverse isoelectric focusing , is within a microscopic range normal to the direction of fluid flow and can be driven by an energy source at button-cell-battery levels favorable to lab-on-a-chip applications. However, existing transverse isoelectric focusing is based on large-dimension (∼4 cm) inert-metal electrodes, unmet with the requirement of miniaturization imposed by emerging high-throughput, high-electrode-density analytical applications. , To address this challenge, electrokinetic microelectrodes can be manufactured by using microfabrication techniques such as e-beam/thermal evaporation and sputtering.…”

“…4−6 Conventional microisoelectric-focusing devices rely on a high voltage supply (>150 V) to generate pH gradients along the fluid-flow direction that is longitudinal to a capillary, thus incompatible to many microelectronics-based lab-on-a-chip technologies. 5,6 Alternatively, transverse isoelectric focusing 7,8 is within a microscopic range normal to the direction of fluid flow and can be driven by an energy source at button-cell-battery levels favorable to lab-on-a-chip applications. However, existing transverse isoelectric focusing is based on large-dimension (∼4 cm) inertmetal electrodes, unmet with the requirement of miniaturization imposed by emerging high-throughput, high-electrodedensity analytical applications.…”

Generation of Natural pH Gradients in Microfluidic Channels for Use in Isoelectric Focusing

“…Higher resolution and lower band diffusion can be achieved by isoelectric focusing (IEF) performed in pre-established pH gradients; the species are separated according to their isoelectric points (p I ). A molecule or larger particle migrates electrophoretically through the pH gradient until it reaches the position in the pH gradient that corresponds to its p I , at which point the net molecular charge on the particle is zero .…”

“…A molecule or larger particle migrates electrophoretically through the pH gradient until it reaches the position in the pH gradient that corresponds to its p I , at which point the net molecular charge on the particle is zero . While initially performed in macroscopic devices, IEF today is usually performed in devices with at least one dimension less than 1 mm, such as fused silica capillaries. , The distance between the electrodes is generally large, as is the applied field. Often the capillaries are filled with a polymeric gel to minimize convective disturbances.…”