Summary
A Technical University of Munich preprint describes synthetic DNA strands carrying flavin chromophores that generate spin-correlated radical pairs. The system can be manipulated with radiofrequency fields and read using optically detected magnetic resonance, with DNA sequence and structure controlling its response.
A preprint from researchers at the Technical University of Munich describes DNA as a nanoscale scaffold for programmable, optically addressable spin systems. By attaching flavin chromophores to synthetic DNA strands, the researchers generated spin-correlated radical pairs (SCRPs) that could be manipulated with radiofrequency fields and monitored through optically detected magnetic resonance (ODMR).
The study, posted on bioRxiv on September 20, 2026, reports that the DNA sequence can tune both the magnetic-resonance response and the associated spin chemistry with single-base resolution. The researchers also found that forming double-stranded DNA changes the ODMR signal, linking the structure of the DNA scaffold to the spin state of the system.
Contents
- How the DNA scaffold works
- Sequence and structure add control
- From proof of concept to possible applications
How the DNA scaffold works
An optically addressable spin system can be controlled or detected through light while its electron-spin behaviour is manipulated with electromagnetic fields. In this work, flavin molecules act as chromophores embedded in synthetic oligonucleotides. Chromophores are light-responsive molecular groups; in the reported constructs, they participate in the formation of radical pairs whose unpaired electrons have correlated spin properties.
The researchers used radiofrequency fields to manipulate these SCRPs and ODMR to read their response. ODMR combines optical detection with magnetic-resonance control: instead of relying only on a conventional electrical or magnetic signal, the system monitors an optical change associated with a spin transition. Pulsed ODMR resolved the spin dynamics on sub-microsecond timescales under ambient conditions.
This arrangement gives the DNA strand two roles. Its chemical sequence positions the flavin components, while the spin-correlated radical pair provides the addressable magnetic behaviour. The result is a molecular system in which the scaffold and the spin chemistry can be designed together.
Sequence and structure add control
The preprint reports that changing the DNA sequence altered both the ODMR response and the related spin chemistry. The reported single-base resolution means that the effect could be tuned through changes as small as one nucleotide in the designed oligonucleotide.
DNA secondary structure supplied another control mechanism. When the synthetic strands formed a duplex, the pulsed ODMR contrast inverted. The researchers interpret this change as evidence that duplex formation switches the spin multiplicity of the radical-pair precursor. Spin multiplicity describes the combined spin configuration of the electrons involved; changing it can alter how a radical pair responds to magnetic fields and how its chemistry proceeds.
This structural response is significant because DNA can be programmed not only through its sequence but also through whether it is single-stranded or paired. That creates a route to molecular spin systems whose behaviour changes when the nucleic-acid scaffold adopts a different configuration.
From proof of concept to possible applications
The researchers demonstrated the platform through proof-of-concept applications that included sensing, programmable positioning of SCRPs and spin-enhanced molecular beacons. These examples use the synthetic accessibility of oligonucleotides—the ability to make DNA strands with designed sequences—to place and tune optically addressable spins at selected molecular positions.
The authors propose that the approach could support quantum sensing, programmable spin arrays, bioimaging and radiofrequency-controlled molecular switches for gene regulation. These are prospective uses of the platform rather than established applications. Their feasibility will depend on how the DNA-hosted systems perform in the more complex environments required for practical sensors, imaging systems or biological regulation.
The work is presented as a bioRxiv preprint, so the findings have not yet appeared as a peer-reviewed journal article. The authors also disclose that Kun Meng and Dominik Bucher are inventors on a Technical University of Munich patent application covering optically addressable spins in oligonucleotides.