T2 Biosystems’ Magnetic Resonance Detection

T2’s proprietary biosensor technology, based on magnetic nanoparticles and miniaturized magnetic resonance, provides rapid diagnostic results with minimal or no sample preparation and with no requirement for optical clarity. Nanoparticles are coated to bind to the target analyte to form clusters within the sample.

T2Bio’s instrument measures the signal from the nuclear spins of hydrogen atoms in water molecules. T2Bio utilizes a small permanent magnet and specialized radiofrequency pulses generated by a coil to measure the signal from the water molecules. Specialized radiofrequency pulses are generated by a coil to excite hydrogen nuclei in water. This same coil is used to detect signal from the hydrogen nuclei from which the T2 relaxation curve is generated.	The series of pulses measure a T2 relaxation curve, which is the water signal measured over the course of several seconds and correlates to the disorder of all of the nuclear spins in water throughout the sample. The T2 value is the monoexponential decay constant calculated from a T2 relaxation curve.
T2Bio’s superparamagnetic nanoparticles are magnetized by the detector and create microscopic non-uniformities in the magnetic field within the sample. The measured T2 signal is influenced by the magnetic particles because they affect the average experience of a water molecule via the microscopic non-uniformities they create. When clustering occurs, particles localize and thereby change the average “experience” of water. Clustering depletes portions of the sample leading to an increase in T2 relaxation. At a high amount of clustering, many water molecules don’t experience microscopic non-uniformities created by superparamagnetic particles and the T2 signal approaches that of water.
The nanoparticles are pre-coated with a binding agent (antibody, oligo, etc) such that in the presence of analyte they cluster. T2’s technology can measure virtually any class of analyte including intact cells, viruses, proteins, small molecules, enzymes and ions. This enables novel test menus on a given cartridge that can be tailored to specific medical settings.