Unique patented technology
The system is comprised of two parts: wet chemical reagents in the assay vial where the immunoreactions take place, and an analytical instrument, the VetReader, for quantification and measuring. The reagent is a two-site heterogeneous immunoassay, with a solid phase consisting of silica microparticles coated with target-specific antibodies. This is used as the solid phase. (See Figure 1.)
The liquid phase consists of a sample buffer with magnetic nanoparticles that have also been coated with target-specific antibodies. These magnetic particles are colloidal, which means that they are small enough to stay in the solution, thus they do not sediment. The magnetic particles are used as the detector. (See Figure 2.)
When the sample containing the target biological substance, i.e. the “marker”, is placed into the reagent vial and the contents are mixed, the targeted marker will be captured by the target-specific antibodies on the silica surface. Target-specific antibodies on the magnetic nanoparticles detect the marker bound to the silica surfaces in a sandwich-binding format. An immune complex is formed. (See Figure 3.)
The reagent vial is placed in the LifeAssays® VetReader and the instrument waits for the reaction to be completed before performing the measurement. During this time, the larger, heavier silica particles will sediment by normal gravity to the bottom of the reagent vial, forming a solid-phase pellet. This pellet will now consist of both silica particles and an immunocomplex of silica-coated magnetic particles. The pellet contains magnetic particles “fished” out of the fluid and possesses magnetic properties. (See Figure 4.)
The internal coil of the LifeAssays® VetReader detects the inductance to give a quantitative measurement of these magnetic properties. The change in inductance is proportional to the amount of magnetic material present in the pellet, in turn showing how much of the selected marker has been bound in the silica-coated-magnetic particle complex.
The internal coil measures the inductance 5 times by pushing the reagent vial in and out of the instrument, creating a “zero” value to use as a comparison each time the vial is lifted out of the instrument. An average raw signal value is created and sent to the system's computer chip where the calculation takes place. The chip contains all of the data specific to the analysis and a self-executable calculation algorithm to calculate the test result in mg/L, which appears on the LifeAssays® VetReader display.
This unique patented system has a number of advantages:
By changing the antibodies on the phases (silica and magnetic nanoparticles), a wide range of potential markers can be targeted. It is the properties of the target-specific antibodies that determine the specificity and sensitivity, and a wide of range of tests can be developed and run based on this system.
No instrument updates needed
All information is stored on one single-use computer chip so the instrument does not need to be updated with new markers or software. A new chip is supplied with every test kit to ensure that the VetReader is always running the latest updates with the correct batch information.
The magnetic immunoassay technique combined with the “one computer chip” allows for quantitative and objective measurements of biological markers. The system delivers numeric values for the diagnosis and monitoring of patients. Very accurate 0.99 correlation compared to ELISA test
Ideal point-of-care system
The system has no optical components, is extremely lightweight (less than 1 kg) and has a small footprint, making it an ideal candidate for point-of-care settings. The system requires minimal maintenance and service and the single-use computer chip ensures seamless delivery of all updates. The unique technology is ideal for complex sample matrices where, for instance, interference from light scattering can be an issue.