Homepage

mmc2021 Abstract Database

Visualising trace element and isotopic distributions in plants using high-resolution secondary ion mass spectrometry imaging (NanoSIMS)

Visualising trace element and isotopic distributions in plants using high-resolution secondary ion mass spectrometry imaging (NanoSIMS)

Session

Stream 3: Chemical Imaging of Biological Samples using Electron, Ion and X-ray Based Techniques

Authors

Dr Katie Moore (1)

Affiliations

1. The University of Manchester

Keywords

NanoSIMS

SIMS

Trace elements

Isotopes

Plants

Abstract text

In this presentation I will discuss the use of high-resolution secondary ion mass spectrometry (NanoSIMS) to localise a range of important and trace elements in plant and bacteria samples. 

Mapping the distribution of elements at the subcellular scale is analytically challenging but necessary in order to understand the mechanisms of uptake of toxic and beneficial elements into plants and crops which can affect the human diet. Subcellular localisation allows us to determine the pathways by which these important elements are taken up by the plant and how they are stored and accumulated in edible tissues. 

 

The NanoSIMS is capable of high spatial resolution chemical imaging (down to 50 nm) and detecting very low elemental concentrations, making it ideally suited for subcellular trace element localisation in biological materials. It is possible to detect a wide range of elements in the periodic table, from hydrogen to uranium, allowing correlation of important lighter elements with the elements of interest which can indicate storage and uptake mechanisms. Furthermore, as this is a mass spectrometry technique, it is possible to detect and image stable isotopes allowing for the possibility of pulse-chase experiments which can provide temporal information about uptake and mobilisation. 

 

The analysis of biological samples with the NanoSIMS, which operates under ultra-high vacuum, is complicated by the need to preserve not only the in vivo structure of the cellular components but also the elemental distribution. There are two approaches for sample preparation, chemical and cryo fixation with the choice dependant on the nature of the elements to be studied. In all cases, the ideal sample preparation methodology workflow is fixation, dehydration, resin embedding and microtomy to create a sample that is flat and high-vacuum compatible. I will discuss various sample preparation methods in the context of the NanoSIMS results presented. 

 

In this presentation I will show how we have used the NanoSIMS to analyse important trace element distributions in rice and wheat, with a particular focus on the effect of micro- and macro-nutrient distributions that affect human health, using isotopically labelled iron and nitrogen, as well as elements which have a deleterious effect on human and plant health such as arsenic and aluminium. I will also present some recent work on bacteria and nanoparticle distributions in plants and algae.

 

Throughout my presentation, I will emphasise how we have used complementary and correlative imaging to gain a deeper understanding of the samples than could be obtained from one technique alone and the advantages of interdisciplinary research.