CE stands for Capillary Electrophoresis and µChip CE stands for microchip CE, the miniaturised version of CE. Shown below is a brief explanation of how CE is carried out in the case of Medimate.
Capillary Electrophoresis is the separation of substances in a capillary under the influence of an electrical field. An electric field exerts a force on the charged particles that find themselves in the field, and if the particles can move they are given a velocity by this force. The force encountered by the particle is dependent on the applied electric field and the charge of the particle. The speed that the particle can reach is further dependent on the resistance it encounters in the capillary. This resistance is determined by the diameter of the particle and the interaction with the medium in the capillary, the viscosity. The result is a unique speed for the different particles which makes it possible to separate them. By applying a conductivity detector after the separation, the discrete zones for each particle can be detected and the quantity of each particle present in the applied sample can be determined.
Medimate's Lab-on-a-Chip is made of glass and is approx. 30 x 4 mm2. The channels that function as capillaries have a diameter of approx. 10 micrometers, which is about the same as one fifth of the diameter of a human hair.
A measurement typically consists of five steps: application, injection, separation, detection and calculation. The five steps of the measurement process are explained in more detail below.
Application of a drop of blood onto the sample channel.
Activation of an electric field. This sucks the positive particles from the applied blood into the channel.
By applying the electric field to the separation channel in 3 the particles are pulled towards the end of the separation channel. Due to the unique speed of the particles in the applied field various types of particle will separate from each other into zones during their journey through the channel. The conductivity across the breadth of the separation channel changes when ions pass by and the conductivity sensor measures these changes. Because the migration speeds are known it is also known in step 4 which peaks in the measurement signal belong to which particles.
In step 5 the concentrations of specific substances are calculated and displayed on the screen.