Metal speciation in biomolecules

Advanced Nuclear and Related Techniques for Metallomics and Nanometallomics

Metallomics, focusing on the global and systematic understanding of the metal uptake, trafficking, role, and excretion in biological systems, has attracted more and more attention. Metal-related nanomaterials, including metallic and metal-containing nanomaterials, have unique properties compared to their macroscale counterparts and therefore require special attention. The absorption, distribution, metabolism, excretion (ADME) behavior of metal-related nanomaterials in the biological systems is influenced by their physicochemical properties, the exposure route, and the microenvironment of the deposition site. Nanomaterials not only may interact directly or indirectly with genes, proteins, and other molecules to bring genotoxicity, immunotoxicity, DNA damage, and cytotoxicity but may also stimulate the immune responses, circumvent tumor resistance, and inhibit tumor metastasis. Because of their advantages of absolute quantification, high sensitivity, excellent accuracy and precision, low matrix effects, and nondestructiveness, nuclear and related analytical techniques have been playing important roles in the study of metallomics and nanometallomics. In this chapter, we present a comprehensive overview of nuclear and related analytical techniques applied to the quantification of metallome and nanometallome, the biodistribution, bioaccumulation, and transformation of metallome and nanometallome in vivo, and the structural analysis. Besides, metallomics and nanometallomics need to cooperate with other -omics, like genomics, proteomics, and metabolomics, to obtain the knowledge of underlying mechanisms and therefore to improve the application performance and to reduce the potential risk of metallome and nanometallome.

Metallomics, elementomics, and analytical techniques

Metallomics is an emerging and promising research field which has attracted more and more attention. However, the term itself might be restrictive. Therefore, the term "elementomics" is suggested to encompass the study of nonmetals as well. In this paper, the application of state-of-the-art analytical techniques with the capabilities of high-throughput quantification, distribution, speciation, identification, and structural characterization for metallomics and elementomics is critically reviewed. High-throughput quantification of multielements can be achieved by inductively coupled plasma-mass spectrometry (ICP-MS) and neutron activation analysis (NAA). High-throughput multielement distribution mapping can be performed by fluorescence-detecting techniques such as synchrotron radiation X-ray fluorescence (SR-XRF), XRF tomography, energy-dispersive X-ray (EDX), proton-induced X-ray emission (PIXE), laser ablation (LA)-ICP-MS, and ion-detecting-based, secondary-ion mass spectrometry (SIMS), while Fourier transform-infrared (FT-IR) and Raman microspectroscopy are excellent tools for molecular mapping. All the techniques for metallome and elementome structural characterization are generally low-throughput, such as X-ray absorption spectroscopy (XAS), NMR, and small-angle X-ray spectroscopy (SAXS). If automation of arraying small samples, rapid data collection of multiple low-volume and -concentration samples together with data reduction and analysis are developed, high-throughput techniques will be available and in fact have partially been achieved.

Combined use of total metal content and size fractionation of metal biomolecules to determine the provenance of pine nuts (Pinus pinea)

Four essential elements (Mn, Ni, Zn, and Cu) and their molecular-size distribution patterns have been determined, for twenty four samples of pine nuts from eight areas in Spain and Portugal (Huelva, Cádiz, Badajoz, Cataluña, Castilla, Madrid, Faro, and Coimbra), by size-exclusion liquid chromatography (SEC) coupled on-line to UV and inductively coupled plasma mass spectrometric (ICP-MS) detection. The variability observed in total element content and the size-exclusion profiles of elements in samples from distant areas were considered as chemical descriptors for characterization of geographic origin. A pattern-recognition technique, the display method principal component analysis, was used as visualization technique to determine the provenance of the pine nuts collected. The results obtained confirmed that size fractionation profiles give more information for assessing the provenance of pine nuts than the total elements composition traditionally used for this purpose. Combination of these chemical descriptors was the most suitable choice for the samples studied. Figure This paper shows the application of an analytical approach based on total elements concentrations and the relative abundance of metal-biomolecules, estimated by the size-exclusion fractions, as chemical descriptors to determine the provenance of pine nuts. Principal component analysis (PCA) has been used as a visualization technique.