The Depixus blog – seeing biology as it really happens

January 22, 2025

What is Depixus MAGNA One™ and how does it work?

Depixus MAGNA One™ provides a powerful new way to study biomolecular interactions at scale between DNA, RNA, proteins, antibodies, small molecules and more.

Based on magnetic force spectroscopy (MFS), Depixus MAGNA One is the first laboratory instrument to deliver direct, real-time measurements of biomolecular interactions across thousands of individual molecules in parallel.

What is magnetic force spectroscopy?

Magnetic force spectroscopy (MFS) is a biophysical technique that directly probes the mechanical properties of individual molecules and their interactions at the nanoscale level.

The technique is performed using apparatus known as magnetic tweezers, which were developed in the 1990s to study supercoiled DNA.1,2 Since then, the technique has been adapted for other applications, but the basic principles remain the same.3,4

A magnetic bead is attached to a molecule tethered to a surface, which is then manipulated by bringing a magnet closer or further away (Figure 1). By measuring the forces required to move the bead, information about the tethered molecule and its interactions with other molecules can be obtained.

Figure 1: Illustration of magnetic force spectroscopy of a single nucleic acid molecular using magnetic tweezers. Taken from Dulin (2024)4 CC-BY 4.0

Magnetic tweezers have been used to study a wide range of biological processes, such as DNA replication and protein folding, deepening our understanding of how biomolecules interact.3,4

However, conventional magnetic force spectroscopy methods are complex, requiring specialist skills and equipment. Until now, there has been no widely available commercial instrument, hence the technique has only been utilized in highly specialized laboratories.

This has prevented magnetic force spectroscopy from becoming a widely accessible technology, despite the valuable insights that it can bring to our understanding of biomolecular interactions.

Depixus MAGNA One makes magnetic force spectroscopy accessible and scalable

At Depixus, we have harnessed the power of magnetic force spectroscopy (MFS) and scaled it up to directly probe thousands of individual biomolecular interactions in parallel in a user-friendly laboratory instrument. By overcoming the previous limitations of this technology, we are opening up exciting opportunities to explore biology and accelerate drug development.

Here’s how it works:

Many thousands of target biomolecules, such as DNA, RNA or proteins, are tethered at one end to the surface of a flow cell in a precise grid array. A tiny paramagnetic bead is attached to the other end of each molecule.

A magnet applies a highly controlled magnetic force to the beads, drawing them closer and pulling on the tethered molecules. The response of each molecule to the force is measured by tracking the position of its bead with nanometer-range precision using total internal reflection microscopy (TIRM).

Light is scattered by each bead when exposed to evanescent field illumination (EFI), and the intensity of this light decays exponentially with distance. By measuring the intensity of the light scattered by each bead with a single pixel within a specialized camera, the vertical height of the bead can be calculated. The grid of molecules inside the flow cell cartridge is carefully aligned to the pixels of the camera, precisely measuring the changes in bead position for each molecule in real time.

The data generated by Depixus MAGNA One can then be used to determine key biophysical parameters, such as the force required to unwind secondary or tertiary structures of nucleic acids or the binding strength of protein-protein interactions. It also provides mechanistic insights into the impact of adding binding proteins, small molecules or other ligands, as well as detailed information about binding kinetics.

Watch this short animation to learn more about how MAGNA One works and what it can do:

Depixus MAGNA One takes magnetic force spectroscopy to a new level

Magnetic force spectroscopy (MFS) has already changed our understanding of how biomolecules interact. Depixus MAGNA One takes this technology to a new level, making it possible to measure thousands of individual interactions in parallel, revealing rich, dynamic data in real time.

Depixus MAGNA One allows you to accurately and dynamically measure kinetic data from thousands of molecules at the same time. With independent parallel analysis of each individual biomolecular interaction, rather than a bulk average, you can see biology as it really happens and get a true representation of what is going on.

This powerful technology opens up new possibilities for exploring biomolecular interactions in the development of novel therapeutics, particularly for challenging targets such as RNA or protein-protein interactions.

Depixus MAGNA One has the potential to be a truly transformative technology for understanding disease mechanisms and accelerating the development of life-changing therapeutics.

Get in touch to find out more about Depixus MAGNA One and how it can help power your research.

References:

1. Smith SB, Finzi L, Bustamante C. Direct mechanical measurements of the elasticity of single DNA molecules by using magnetic beads. Science. 1992 Nov 13;258(5085):1122-6. doi: 10.1126/science.1439819

2. Strick TR, Allemand JF, Bensimon D, Bensimon A, Croquette V. The elasticity of a single supercoiled DNA molecule. Science. 1996 Mar 29;271(5257):1835-7. doi: 10.1126/science.271.5257.1835

3.Sarker R. and Rybenkov V. (2016) A Guide to Magnetic Tweezers and Their Applications Front. Phys. 4 doi: 10.3389/fphy.2016.00048

4. Dulin, D. (2024). An Introduction to Magnetic Tweezers. In: Heller, I., Dulin, D., Peterman, E.J. (eds) Single Molecule Analysis. Methods in Molecular Biology, vol 2694. Humana, New York, NY. doi: 10.1007/978-1-0716-3377-9_18