The MICT® system from MagnaBioAnalytics, is a desktop instrument designed for the detection and quantification of enzymes in industrial environments.

The format of MICT assays is similar to that of standard home pregnancy tests. In MICT assays, however, small magnetic nanoparticles replace the gold or colored latex particles used in visually read tests. These nanoparticles have similar flow and capture characteristics to their colored analogues, however in the MICT technology system, a magnetic measurement of the capture line is made. The magnetic measurement is directly related (quantitatively) to the amount of accumulated magnetic material in the capture region. The magnetic measurement requires the excitation of the nanoparticles in a magnetic field.

This magnetic field is provided by way of a C-shaped electromagnet, while the magnetic measurement is performed by an array of thin film induction coils. The format of the capture line, as well as the geometry, position, material selection and electronics, all contribute to the sensitive nature and quantitative ability of the measurement.

The graphic to the left helps to illustrate the sensitivity advantage offered by MICT. In all immuno-chromatographic tests, the capture region extends throughout the depth of the membrane, as does particle accumulation in the completed test. In optically read assays (visual or reflectance), only the accumulation of particles on the top surface can be detected. Typically depth resolution is limited to 10μ in membranes that are approximately 200μ thick. In MICT, the entire particle distribution can be resolved by way of a magnetic measurement.

The assay principle is an immunochromatographic sandwich assay, using conjugated superparamagnetic nanoparticles as the labeling agent along with a magnetic-induction detection platform. In addition to a test line (T line) and a built-in quality control line (C line), a hook effect report line (H line) is added which will prevent underreporting of the concentration in case of a high-dose hook-effect.

MICT® TECHNOLOGY ADVANTAGES

Electronically read lateral flow instruments typically employ optical transmission or reflectance techniques to quantify the accumulation of particles in the test region. Such techniques suffer from numerous inaccuracies which may be caused by:

• Non-uniform distribution of particles in the capture region. This can be a problem due to the small spot size of laser diodes used in the measurement. In contrast, MICT technology uses a volumetric measurement technique, with a cross sectional area of approximately 2 mm². This is considerably larger than the micron-scale measurements made with laser diodes.
• Optical interferences from other components in the sample. Such interferences can mask the colored particles intended to be detected. Flow dynamics, in which the distribution of particles can sometimes be pulled away from the surface of the test strip, can also be a factor leading to inaccuracies. Both of these factors serve to mask the particles intended to be detected. By their nature, the magnetic moment from the SPMP cannot be masked or optically hidden from the MICT detector elements.

	Conventional Immunoassay	MAR Magnetic Immunoassay
Antibody Conjugate	Gold Colloid Enzyme Fluorophores Luminescent Molecules	Superparamagnetic Particles 60-380 nm
Excitation	Enzyme substrate laser or visible light	Oscillating Magnetic Field
Detection	Visual Absorption Transmission Reflection	Measures magnetization of magnetic Particles

	Conventional Immuno- assay	MAR Magnetic Immuno- assay
Antibody Conjugate	Gold Colloid Enzyme Fluoro- phores Luminescent Molecules	Superpara- magnetic Particles 60-380 nm
Excitation	Enzyme substrate laser or visible light	Oscillating Magnetic Field
Detection	Visual Absorption Transmission Reflection	Measures magneti- zation of magnetic Particles