Elemental Imaging in Biological Systems

Elemental imaging has emerged as a powerful suite of techniques for mapping the distribution, concentration and chemical state of elements within biological specimens across scales ranging from whole tissues to the subcellular level. By harnessing the penetration and elemental specificity of X-rays, researchers combine X-ray fluorescence (XRF) to detect trace metal concentrations with spectroscopic approaches such as X-ray absorption near-edge structure (XANES) to reveal oxidation states and coordination environments. Advances in synchrotron-based and laboratory sources, coupled with high-resolution optics and sensitive detectors, allow sub-micrometre spatial resolution whilst preserving physiological context through cryogenic and in vivo methodologies. These capabilities have deepened our understanding of metalloprotein function, metal-driven biochemical pathways and metal dyshomeostasis in health and disease. The development of complementary imaging modes, including scanning transmission X-ray microscopy (STXM), electron microscopy and hybrid optical–X-ray workflows, has further enabled multimodal correlation of elemental maps with ultrastructure, advancing applications from neuroscience to microbiology and environmental bioanalysis.

Research from Nature Portfolio

Recent studies have extended in vivo elemental imaging by evolving XANES spectroscopy into a fluorescence imaging modality termed φXANES. This approach preserves native hydration and avoids radiation-induced artefacts to map metal–protein coordination within living organisms. By applying φXANES to simple animal models, researchers have visualised shifts in redox environments and metal-binding sites associated with physiological and stress responses. Such in situ spectroscopic imaging now offers the potential to track metal trafficking and speciation dynamics across tissues, bridging molecular detail and whole-organism physiology.

Elemental Imaging in Biological Systems publication trend

The graph below shows the total number of articles in elemental imaging in biological systems across all publications each year (not limited to Nature Index journals).

Technical terms

φXANES: Fluorescence imaging modality combining XANES spectroscopy to map in vivo metal–protein coordination environments.

X-ray fluorescence (XRF): Analytical technique that detects characteristic secondary X-rays emitted by elements to quantify and map their distribution.

X-ray absorption near-edge structure (XANES): Spectroscopic method probing the electronic structure and oxidation state of specific elements by measuring absorption edges.

Scanning transmission X-ray microscopy (STXM): Imaging technique using focused X-rays to produce high-resolution elemental and chemical maps of thin specimens.

Cryofixation: Sample preparation method that rapidly freezes specimens to preserve native structure and elemental distribution for imaging.

References

1. Imaging metals in biology: balancing sensitivity, selectivity and spatial resolution. Chemical Society Reviews (2015).
2. φXANES: In vivo imaging of metal-protein coordination environments. Scientific Reports (2016).
3. Soft X-ray Fluorescence and Near-Edge Absorption Microscopy for Investigating Metabolic Features in Biological Systems: A Review. International Journal of Molecular Sciences (2023).
4. Impact of Sample Preparation Methods on Single-Cell X-ray Microscopy and Light Elemental Analysis Evaluated by Combined Low Energy X-ray Fluorescence, STXM and AFM. Molecules (2023).
5. KMnO4/Pb staining allows uranium free imaging of tissue architectures in low vacuum scanning electron microscopy. npj Imaging (2024).