There is a growing need for alternative in vivo models in biomedical research due to ethical considerations, regulatory restrictions, and the drive to reduce reliance on traditional mammalian models. The 3Rs principle (Replacement, Reduction, and Refinement) encourages the development of models that minimize animal use while maintaining scientific rigor. The chicken embryo is emerging as a powerful alternative, offering a versatile and ethically favourable platform for studying nanoparticle distribution, toxicology, and drug delivery. Its rapid development and well-defined vasculature make it particularly suitable for in vivo studies, while its ex ovo cultivation further enhances accessibility and manipulation possibilities.^[1]

In this study, laser ablation-inductively coupled plasma-time-of-flight mass spectrometry (LA-ICP-TOFMS) was employed to generate high-resolution elemental images from cross-sections of whole embryos, enabling a comprehensive multi-organ spatial distribution analysis of endogenous elements. This approach allows for the simultaneous investigation of major organs such as the heart, liver, stomach, intestine, gall bladder, bones, and brain within a single tissue thin section, providing valuable insights into organ-specific elemental signatures and biodistribution patterns.

To further enhance data interpretation, uniform manifold approximation and projection (UMAP)^[2] clustering was applied to the spatially resolved LA-ICP-TOFMS dataset, enabling data-depended classification of elemental signatures across different tissues. This dimensionality reduction method facilitates the identification of subtle biochemical variations and highlights the advantages of high-dimensional clustering for spectral analysis, especially in bioimaging.

The findings demonstrate the high potential of the chicken embryo as an alternative in vivo model for biomedical applications in analytical chemistry, offering a scientifically robust and ethically aligned platform for studying complex biological processes. In combination with LA-ICP-TOFMS, this model provides exceptional spatial resolution, making it a powerful platform for investigating element-specific distributions and their physiological relevance.

References

[1] D. Ribatti Reproductive Toxicology, 2017, 70, 97-101.

[2] L. McInnes, J. Healy, J. Melville arXiv, 2018.