A study recently published in Nature Photonics introduces a new technique, magnetofluorescence vibrational microspectroscopy (MFFMS), for probing quantum effects in biological systems. The method focuses on the behavior of radical pairs in a magnetic field, specifically their interactions with proteins and flavin compounds. The researchers note that MFFMS is highly sensitive and can provide valuable insights into the role of base pair dynamics in biological processes.
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Advances in detection technology
Quantum biology studies the role of quantum phenomena in biological processes such as electron transfer, enzymatic reactions, and magnetic induction. Studying these effects often requires testing biomolecules at extremely low concentrations or in complex environments. However, traditional detection methods may not provide the sensitivity or specificity needed to capture these subtle interactions.
Recent advances in fluorescence detection technology allow researchers to monitor small changes in signal caused by external magnetic fields. These improvements are essential for studying protein-ligand interactions and understanding how quantum effects affect biological systems at the molecular level.
MFFMS: A new technique to explore quantum effects
In this study, the researchers developed an MFFMS to study the quantum behavior of radical pairs in biological systems. Their setup included a custom-built spectromicroscope equipped with a high numerical aperture objective lens, a continuous wave laser diode for excitation, and optical filters to isolate the fluorescence signal. The system achieves a detection volume of just 0.54 femtoliters and can capture changes as small as 0.2% induced by magnetic fields.
Fluorescence signals were recorded using a single-photon avalanche diode (SPAD) and an electron-multiplying charge-coupled device (EMCCD) camera. Custom-designed Helmholtz coils generate precise magnetic fields for the experiments. To gain a deeper understanding of base pair dynamics, the researchers studied the interactions of flavin mononucleotide (FMN) with proteins such as hen egg white lysozyme (HEWL) and bovine serum albumin (BSA).
To ensure reliable results, the team used digital key detection to remove noise and improve signal clarity. Data acquisition was managed through LabVIEW, and analysis was performed using MATLAB and Python. This combination provides insight into the mechanisms of radical pairing and protein-flavin binding.
Key findings
This study demonstrates that MFFMS can reliably detect the magnetic field effect (MFE) on radical pairs, providing valuable insight into the quantum behavior of radical pairs. For example, in the photoinduced reaction between FMN and HEWL, the researchers observed a magnetic field effect of approximately -1%, detected at approximately 7 photons. The high sensitivity and strong signal-to-noise ratio (N = 185) of the method demonstrate its ability to detect subtle interactions in complex biological systems.
The experiments also revealed clear differences in how FMN behaves when bound to different proteins. FMN associated with HEWL exhibits a negative MFE involving base pairs generated from triplets. In contrast, FMN bound to BSA exhibited a positive MFE at higher flow rates, indicating the formation of singlet-derived radical pairs. These findings highlight the complexity of protein-flavin interactions and the importance of binding dynamics in radical pair formation.
The researchers also noted that photolysis affects the stability of flavins, which in turn affects protein interactions and the behavior of the radical pair. Combining fluorescence correlation spectroscopy (FCS) with digital lock detection provided detailed insight into the dynamics of the radical pair. This work improves the magnetic field sensitivity of the MFFMS, positioning it as a powerful tool to advance research into quantum biological phenomena such as magnetic induction.
Applications of MFFMS in biological research
MFFMS technology has important applications in biochemistry and quantum biology, enabling researchers to study quantum effects in a variety of biological systems, including processes such as animal induction and enzymatic reactions. MFFMS may also contribute to advances in medical diagnostics and treatments by revealing how magnetic fields affect biochemical processes.
The single-molecule sensitivity of MFFMS makes it a promising tool for drug discovery and development, particularly targeting flavin-dependent enzymes and proteins. Understanding how drug candidates bind and interact with these molecules could help design more effective therapeutics.
Combined with advanced imaging techniques, MFFMS may also provide new opportunities to study cellular dynamics, enzyme activity, signal transduction, and metabolic processes. These capabilities make it a valuable tool for studying flavoproteins and their role in various cellular functions. Furthermore, the ability to measure the effects of magnetic fields at the molecular level may aid in the development of biosensors and imaging systems for monitoring biological processes in real time.
Reference magazines
Antill, L. M., et al . (2025). An introduction to vibrational spectroscopy from fluorescence to the study of quantum effects in biology. Nat. Photon . DOI: 10.1038/s41566-024-01593-x, https://www.nature.com/articles/s41566-024-01593-x#Bib1
