Overview - Siemens Healthineers Atellica VTLi User Manual

Appendix C - Theory of Operations

Overview

The Atellica VTLi Immunoassay Analyzer uses Magnotech® technology. Magnotech
is a biosensor technology that uses magnetic nanoparticles to measure picomolar
concentrations of target substances in the sample in a matter of minutes.
The test is integrated in the cartridge. A cartridge is disposable and can only be used once.
When the cartridge is inserted in the handheld analyzer, the cartridge fills automatically
after applying a few droplets of the sample. Once filled, no other fluid movement is
required. The entire test process within the cartridge is executed by controlled movement of
the magnetic nanoparticles within the cartridge using external magnetic fields.
The cartridge is constructed primarily from plastic components with an RFID containing
cartridge-specific information like expiry date and lot number. The analyzer unit contains
the electromagnets, an optical detection system, control electronics, software, and a read-
out display.
Coated with appropriate ligand molecules, the magnetic nanoparticles bind to the target
protein molecules in the sample.
The captured target molecules can then be pulled towards the active detection surface
using the binding magnet [1]. There a specific binding can take place that binds the
magnetic nanoparticles to the surface.
A second magnetic field is then generated (washing magnet [2]) to pull unbound magnetic
nanoparticles away from the active surface. A very fast and accurately controlled separation
between bound and unbound magnetic nanoparticles is thereby achieved.
In the final phase, the number of bound nanoparticles is measured using an optical
technique based on frustrated total internal reflection.
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