Could biological tissue preservation methods change chemical elements proportion measured by energy dispersive X-ray spectroscopy?


Energy dispersive X-ray spectroscopy (EDS) is a powerful technical tool used in the biomedical field to investigate the proportion of chemical elements of interest in research, such as heavy metal bioaccumulation and the enzymatic cofactors and nanoparticle therapy in various pathologies. However, the correct evaluation of the proportion of the elements is subject to some factors, including the method of sample preservation. In this study, we seek to investigate the effect of biological tissue preservation methods on the proportion of chemical elements obtained by the EDS methodology. For such, we used EDS to measure the proportion of chemical elements with biomedical interest in preserved livers, using three common methods for preserving biological tissues: (a) freezing, (b) paraformaldehyde fixative solution, and (c) Karnovsky solution. We found an increased level of sodium and reduced contents of potassium and copper in samples fixed in fixative solutions, when compared to frozen samples (p < 0.05). Our data indicate that preservation methods can change the proportion of chemical elements in biological samples, when measured by EDS. Frozen preservation should be preferred to retain the actual chemical content of samples and allow a correct assessment of the proportion of their elements.

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The authors are thankful to the “Núcleo de Microscopia e Microanálise - NMM” of the Federal University of Viçosa (UFV); Almeida, E. L. M. for the insights in the discussion; Sacramento, E. for English language editing; “Programa de Pós-Graduação em Biologia Celular e Estrutural” of UFV for the resources to perform the analyses; and “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior” (CAPES) for the L. C. M. Ladeira Ph.D. scholarship provided (process nº 88882.436984/2019-01).

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Correspondence to Luiz Carlos Maia Ladeira.

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Ladeira, L.C.M., dos Santos, E.C., Valente, G.E. et al. Could biological tissue preservation methods change chemical elements proportion measured by energy dispersive X-ray spectroscopy?. Biol Trace Elem Res 196, 168–172 (2020).

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  • Energy dispersive X-ray spectroscopy
  • Fixative methods
  • Chemical element proportion