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Innate immune systems alter the concentrations of trace elements in host niches in response to invading pathogens during infection. This work reports the interplay between d-block metal ions and their associated biomolecules using hyphenated elemental techniques to spatially quantify both elemental distributions and the abundance of specific transport proteins. Here, lung tissues were collected for analyses from naïve and Streptococcus pneumoniae-infected mice fed on a zinc-restricted or zinc-supplemented diet. Spatiotemporal distributions of manganese (55Mn), iron (56Fe), copper (63Cu), and zinc (66Zn) were determined by quantitative laser ablation-inductively coupled plasma-mass spectrometry. The murine transport proteins ZIP8 and ZIP14, which are associated with zinc transport, were also imaged by incorporation of immunohistochemistry techniques into the analytical workflow. Collectively, this work demonstrates the potential of a single instrumental platform suitable for multiplex analyses of tissues and labelled antibodies to investigate complex elemental interactions at the host-pathogen interface. Further, these methods have the potential for broad application to investigations of biological pathways where concomitant measurement of elements and biomolecules is crucial to understand the basis of disease and aid in development of new therapeutic approaches.

Nanoparticles are produced at accelerating rates, are increasingly integrated into scientific and industrial applications, and are widely discharged into the environment. Analytical techniques are required to characterize parameters such as particle number concentrations, mass and size distributions, molecular and elemental compositions, and particle stability. This is not only relevant to investigate their utility for various industrial or medical applications and for controlling the manufacturing processes but also to assess toxicity and environmental fate. Different analytical strategies aim to characterize certain facets of particles but are difficult to combine to retrieve relevant parameters coherently and to provide a more comprehensive picture. In this work, we demonstrate the first online hyphenation of optofluidic force induction (OF2i) with Raman spectroscopy and inductively coupled plasma-time-of-flight-mass spectrometry (ICP-TOFMS) to harness their complementary technology-specific advantages and to promote comprehensive particle characterizations. We optically trapped individual particles on a weakly focused vortex laser beam by aligning a microfluidic flow antiparallelly to the laser propagation direction. The position of particles in this optical trap depended on the hydrodynamic diameter and therefore enabled size calibration as well as matrix elimination. Additionally, laser light scattered on particles was analyzed in a single particle (SP) Raman spectroscopy setup for the identification of particulate species and phases. Finally, particles were characterized regarding elemental composition and their distributions in mass and size using SP ICP-TOFMS. In a proof of concept, we analyzed polystyrene-based microplastic and TiO2 nanoparticles and demonstrated the opportunities provided through the coupling of OF2i with SP Raman and SP ICP-TOFMS.

Metal ions are required by all organisms for the chemical processes that support life. However, in excess they can also exert toxicity within biological systems. During infection, bacterial pathogens such as Streptococcus pneumoniae are exposed to host-imposed metal intoxication, where the toxic properties of metals, such as copper, are exploited to aid in microbial clearance. However, previous studies investigating the antimicrobial efficacy of copper in vivo have reported variable findings. Here, we use a highly copper-sensitive strain of S. pneumoniae, lacking both copper efflux and intracellular copper buffering by glutathione, to investigate how copper stress is managed and where it is encountered during infection. We show that this strain exhibits highly dysregulated copper homeostasis, leading to the attenuation of growth and hyperaccumulation of copper in vitro. In a murine infection model, whole-tissue copper quantitation and elemental bioimaging of the murine lung revealed that infection with S. pneumoniae resulted in increased copper abundance in specific tissues, with the formation of spatially discrete copper hot spots throughout the lung. While the increased copper was able to reduce the viability of the highly copper-sensitive strain in a pneumonia model, copper levels in professional phagocytes and in a bacteremic model were insufficient to prosecute bacterial clearance. Collectively, this study reveals that host copper is redistributed to sites of infection and can impact bacterial viability in a hypersusceptible strain. However, in wild-type S. pneumoniae, the concerted actions of the copper homeostatic mechanisms are sufficient to facilitate continued viability and virulence of the pathogen. IMPORTANCE Streptococcus pneumoniae (the pneumococcus) is one of the world's foremost bacterial pathogens. Treatment of both localized and systemic pneumococcal infection is becoming complicated by increasing rates of multidrug resistance globally. Copper is a

Since its inception in the early 80s, inductively coupled plasma-mass spectrometry has developed to the method of choice for the analysis of elements in complex biological systems. High sensitivity paired with isotopic selectivity and a vast dynamic range endorsed ICP-MS for the inquiry of metals in the context of biomedical questions. In a stand-alone configuration, it has optimal qualities for the biomonitoring of major, trace and toxicologically relevant elements and may further be employed for the characterisation of disrupted metabolic pathways in the context of diverse pathologies. The on-line coupling to laser ablation (LA) and chromatography expanded the scope and application range of ICP-MS and set benchmarks for accurate and quantitative speciation analysis and element bioimaging. Furthermore, isotopic analysis provided new avenues to reveal an altered metabolism, for the application of tracers and for calibration approaches. In the last two decades, the scope of ICP-MS was further expanded and inspired by the introduction of new instrumentation and methodologies including novel and improved hardware as well as immunochemical methods. These additions caused a paradigm shift for the biomedical application of ICP-MS and its impact in the medical sciences and enabled the analysis of individual cells, their microenvironment, nanomaterials considered for medical applications, analysis of biomolecules and the design of novel bioassays. These new facets are gradually recognised in the medical communities and several clinical trials are underway. Altogether, ICP-MS emerged as an extremely versatile technique with a vast potential to provide novel insights and complementary perspectives and to push the limits in the medical disciplines. This review will introduce the different facets of ICP-MS and will be divided into two parts. The first part will cover instrumental basics, technological advances, and fundamental considerations as well as traditional and current a

Breast cancer is the leading cause of cancer death in woman and tremendous efforts are undertaken to limit its dissemination and to provide effective treatment. Various histopathological parameters are routinely assessed in breast cancer biopsies to provide valuable diagnostic and prognostic information. MMP-11 and CD45 are tumor-associated antigens and potentially valuable biomarkers for grading aggressiveness and metastatic probability. This paper presents methods for quantitative and multiplexed imaging of MMP-11 and CD45 in breast cancer tissues and investigates their potential for improved cancer characterization and patient stratification. An immunohistochemistry-assisted laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method was successfully developed and optimized using lanthanide-tagged monoclonal antibodies as proxies to determine spatial distributions and concentrations of the two breast cancer biomarkers. The labeling degree of antibodies was determined via size exclusion-ICP-tandem mass spectrometry (SEC-ICP-MS/MS) employing online calibration via post-column isotope dilution analysis (IDA). The calibration of spatial distributions of labeled lanthanides in tissues was performed by ablating mold-prepared gelatin standards spiked with element standards. Knowledge of labeling degrees enabled the translation of lanthanide concentrations into biomarkers concentrations. The k-means clustering was used to select tissue areas for statistical analysis and mean concentrations were compared for sets of metastatic, non-metastatic and healthy samples. MMP-11 was expressed in stroma surrounding tumor areas, while CD45 was predominantly found inside tumor areas with high cell density. There was no significant correlation between CD45 and metastasis (P = 0.70); however, MMP-11 was significantly up-regulated (202%) in metastatic samples compared to non-metastatic (P = 0.0077) and healthy tissues (P = 0.0087).

Inductively coupled-plasma mass spectrometry (ICP-MS) has transformed our knowledge on the role of trace and major elements in biology and has emerged as the most versatile technique in elemental mass spectrometry. The scope of ICP-MS has dramatically changed since its inception, and nowadays, it is a mature platform technology that is compatible with chromatographic and laser ablation (LA) systems. Over the last decades, it kept pace with various technological advances and was inspired by interdisciplinary approaches which endorsed new areas of applications. While the first part of this review was dedicated to fundamentals in ICP-MS, its hyphenated techniques and the application in biomonitoring, isotope ratio analysis, elemental speciation analysis, and elemental bioimaging, this second part will introduce relatively current directions in ICP-MS and their potential to provide novel perspectives in the medical sciences. In this context, current directions for the characterisation of novel nanomaterials which are considered for biomedical applications like drug delivery and imaging platforms will be discussed while considering different facets of ICP-MS including single event analysis and dedicated hyphenated techniques. Subsequently, immunochemistry techniques will be reviewed in their capability to expand the scope of ICP-MS enabling analysis of a large range of biomolecules alongside elements. These methods inspired mass cytometry and imaging mass cytometry and have the potential to transform diagnostics and treatment by offering new paradigms for personalised medicine. Finally, the interlacing of immunochemistry methods, single event analysis, and functional nanomaterials has opened new horizons to design novel bioassays which promise potential as assets for clinical applications and larger screening programs and will be discussed in their capabilities to detect low-level proteins and nucleic acids.

The analysis of natural and anthropogenic nanomaterials (NMs) in the environment is challenging and requires methods capable to identify and characterise structures on the nanoscale regarding particle number concentrations (PNCs), elemental composition, size, and mass distributions. In this study, we employed single particle inductively coupled plasma-mass spectrometry (SP ICP-MS) to investigate the occurrence of NMs in the Melbourne area (Australia) across 63 locations. Poisson statistics were used to discriminate between signals from nanoparticulate matter and ionic background. TiO2-based NMs were frequently detected and corresponding NM signals were calibated with an automated data processing platform. Additionally, a method utilising a larger mass bandpass was developed to screen for particulate high-mass elements. This procedure identified Pb-based NMs in various samples. The effects of different environmental matrices consisting of fresh, brackish, or seawater were mitigated with an aerosol dilution method reducing the introduction of salt into the plasma and avoiding signal drift. Signals from TiO2- and Pb-based NMs were counted, integrated, and subsequently calibrated to determine PNCs as well as mass and size distributions. PNCs, mean sizes, particulate masses, and ionic background levels were compared across different locations and environments.

BACKGROUND: Elements are the basis of life on Earth, whereby organisms are essentially evolved chemical substances that dynamically interact with each other and their environment. Determining species elemental quotas (their elementome) is a key indicator for their success across environments with different resource availabilities. Elementomes remain undescribed for functionally diverse dinoflagellates within the family Symbiodiniaceae that includes coral endosymbionts. We used dry combustion and ICP-MS to assess whether Symbiodiniaceae (ten isolates spanning five genera Breviolum, Cladocopium, Durusdinium, Effrenium, Symbiodinium) maintained under long-term nutrient replete conditions have unique elementomes (six key macronutrients and nine micronutrients) that would reflect evolutionarily conserved preferential elemental acquisition. For three isolates we assessed how elevated temperature impacted their elementomes. Further, we tested whether Symbiodiniaceae conform to common stoichiometric hypotheses (e.g., the growth rate hypothesis) documented in other marine algae. This study considers whether Symbiodiniaceae isolates possess unique elementomes reflective of their natural ecologies, evolutionary histories, and resistance to environmental change. RESULTS: Symbiodiniaceae isolates maintained under long-term luxury uptake conditions, all exhibited highly divergent elementomes from one another, driven primarily by differential content of micronutrients. All N:P and C:P ratios were below the Redfield ratio values, whereas C:N was close to the Redfield value. Elevated temperature resulted in a more homogenised elementome across isolates. The Family-level elementome was (C19.8N2.6 P1.0S18.8K0.7Ca0.1) · 1000 (Fe55.7Mn5.6Sr2.3Zn0.8Ni0.5Se0.3Cu0.2Mo0.1V0.04) mmol Phosphorous-1 versus (C25.4N3.1P1.0S23.1K0.9Ca0.4) · 1000 (Fe66.7Mn6.3Sr7.2Zn0.8Ni0.4Se0.2Cu0.2Mo0.2V0.05) mmol Phosphorous -1 at 27.4 ± 0.4 °C and 30.7 ± 0.01 °C, respectively. Symbiodiniaceae isolates tested h

Increasing anthropogenic pressure on coral reefs is creating an urgent need to understand how and where corals can proliferate both now and under future scenarios. Resolving environmental limits of corals has progressed through the accurate identification of corals’ ‘realised ecological niche’. Here we expand the ecological niche concept to account for corals’ ‘biogeochemical niche’ (BN), defined as the chemical space in which a coral is adapted to survive, and which is identifiable by a unique quantity and proportion of elements (termed “elementome”). BN theory has been commonly applied to other taxa, successfully predicting species distributions and stress responses by their elementomes. Here, we apply the BN theory to corals for the first time, by using dry combustion and inductively coupled plasma–mass spectrometry (ICP-MS) to determine five key macronutrients and thirteen trace elements of four diverse scleractinian coral species from the Great Barrier Reef (GBR): Acropora hyacinthus; Echinopora lamellosa; Pocillopora cf. meandrina; and Pocillopora cf. verrucosa. The elementomes were investigated in both host and Symbiodiniaceae, and the latter had the highest elemental concentrations (except molybdenum). Each coral species associated with distinct members of the genus Cladocopium (determined by ITS2 analysis) with photo-physiological data suggesting specialisation of Cladocopium functional biology. Distinct endosymbiont community structure and functioning between corals with different elementomes confirms that BN theory holds as metabolic compatibility alters across host–symbiont associations. Additional work is needed to understand the plasticity of coral elementomes, and in turn BN, over space and time to aid predictions on coral distribution and survival with environmental change.

Six Australian and five overseas complementary medicines (CM) and meal replacement shake products were analysed for potential adulteration with two common active pharmaceutical ingredients, caffeine and sibutramine, using thin-layer chromatography and mass spectrometry. The declared amount of caffeine in each product was also reviewed. Finally, the products were examined for heavy metal contamination using inductively coupled plasma-mass spectrometry. The results showed that there was no detected adulteration of either caffeine (for those products that did not list caffeine as an ingredient) or sibutramine in the 11 products; however, based on the product labels, one Australian and one overseas (two in total) CM product contained more than the maximum daily safety limit (400 mg) of caffeine. Potentially excessive lead and/or chromium was detected in six products, including four Australian products and two products purchased online. One Australian CM product appeared to contain these heavy metals at concentrations at, or exceeding, the safety limits specified in the United States Pharmacopeia or set by the World Health Organization. The overconsumption of caffeine and heavy metals has the potential of causing significant health effects in consumers.

Per- and polyfluoroalkyl substances (PFAS) represent a large group of synthetic organic compounds which exhibit unique properties and have been extensively used for consumer and industrial products, resulting in a widespread presence in the environment. Regulation requiring PFAS monitoring has been implemented worldwide due to their potential health and eco-toxicological effects. Targeted methods are commonly used to monitor between twenty to forty PFAS compounds, representing only a small fraction of the number of compounds that may be present. Consequently, there is an increasing interest in complementary non-targeted methods to screen and identify unknown PFAS compounds with the aim to improve knowledge and to generate more accurate models regarding their environmental mobility and persistence. This work details the development of a method that simultaneously provided targeted and non-targeted PFAS analysis. Ultra-high performance liquid chromatography (UHPLC) was coupled to ion mobility-quadrupole time of flight-mass spectrometry (IMS-QTOF-MS) and used to quantify known and screen unknown PFAS in environmental samples collected within the greater Sydney basin (Australia). The method was validated for the quantification of 14 sulfonate-based PFAS, and a non-targeted data analysis workflow was developed using a combination of mass defect analysis with common fragment and neutral loss filtering to identify fluorine-containing species. The optimised method was applied to the environmental samples and enabled the determination of 3-7 compounds from the targeted list and the detection of a further 56-107 untargeted PFAS. This simultaneous analysis reduces the complexity of multiple analyses, and allows for greater interrogation of the full PFAS load in environmental samples.

This work demonstrates the first forensic application of GC-ICP-MS for improved investigations of volatile organic compounds originating from a decomposing body. Volatile organic compounds were extracted from the headspace of human remains using sorbent tubes over a total time of 39 days. To account for naturally abundant species, control sites were prepared and sampled accordingly. All samples were spiked with an internal standard to minimise drift effects and errors during sample preparation and further analysis. Compound independent quantification was possible from a single chromatogram with a standard mix containing volatile pesticide compounds representing different mass fractions of target elements for calibration. Phosphorus, sulphur and chlorine were investigated as biologically relevant elements, which potentially form detectable volatile species during decomposition. The limits of detection of these elements in the headspace were 0.7, 5.4 and 1.6 ng/L, respectively. For sulphur, we identified abundant species which increased in concentrations of up to 1310 ng/L in the headspace above the remains. The concentrations were time dependent and show potential as forensic markers to determine post-mortem intervals or decomposition states. The universal quantification, standardisation and the high sensitivity of GC-ICP-MS augments traditional GC-MS analyses.

Single particle (SP) and single cell (SC) inductively coupled plasma-mass spectrometry (ICP-MS) are gaining increasing momentum in environmental and medical sciences for the analysis of nanoparticles, microstructures, and individual cells. This work presents an open-source Python-based SP/SC ICP-MS data processing platform with an interactive graphical user interface. The program guides users through the analysis of large data sets and uses efficient and transparent algorithms. Gaussian and Poisson-based data filtering enables fit for purpose thresholding of particle signals from background noise. Implementation of windowed filters extends applicability of the software to SP laser ablation-ICP-MS and other data sets that contain drifting or variable backgrounds. SP or SC signals recorded with multiple data points are integrated and several distinct calibration and processing pathways may be used to determine masses, sizes, and number concentrations, or to calculate intracellular concentrations. Relevant parameters including means, medians, ionic background levels and limits of analysis are automatically calculated and visualised together with histograms of raw and calibrated data. As a proof of principle, the developed data processing platform was employed to characterise TiO2 nanoparticles in surface water, microplastic particles in soil and the C content across individual cells.

© 2020 The Royal Society of Chemistry. This work introduces a new method for immuno-mass spectrometry imaging via quadrupole-based laser ablation-inductively coupled plasma-mass spectrometry instruments that is matched to the abundance of elements in biological tissues. Manipulation of ion-optics and quadrupole mass filter parameters provided increased transmission of low level high-mass elements, which are typically used as labels for antibodies, at the expense of highly abundant endogenous low-mass elements. Transmission of mid-mass elements such as transition metals was only slightly affected. The implications for mass resolution and background signals are critically discussed and signal to noise ratios and imaging capabilities are compared to those obtained from a standard method. This novel approach resulted in a 6-fold improved signal to noise ratio for lanthanides that are routinely used as elemental labels for antibodies to target protein distributions in biological tissues. This increase in signal intensity, enhanced contrasts, lower limits of detection and the potential to improve spatial resolution contributed to enhanced imaging and trace analyses, as demonstrated by imaging murine brain sections of the hippocampal system and substantia nigra.

A dysregulation in the homeostasis of metals such as copper, iron and zinc is speculated to be involved in the pathogenesis of tauopathies, which includes Alzheimer's disease (AD). In particular, there is a growing body of evidence to support a role for iron in facilitating the hyperphosphorylation and aggregation of the tau protein into neurofibrillary tangles (NFTs) - a primary neuropathological hallmark of tauopathies. Therefore, the aim of this study was to characterize the spatial and temporal brain metallomic profile in a mouse model of tauopathy (rTg(tauP301L)4510), so as to provide some insight into the potential interaction between tau pathology and iron. Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), our results revealed an age-dependent increase in brain iron levels in both WT and rTg(tauP301L)4510 mice. In addition, size exclusion chromatography-ICP-MS (SEC-ICP-MS) revealed significant age-related changes in iron bound to metalloproteins such as ferritin. The outcomes from this study may provide valuable insight into the inter-relationship between iron and tau in ageing and neurodegeneration.

This work introduces new methods to characterize dispersions of small-diameter or low-mass-fraction nanoparticles (NPs) by single-particle inductively coupled plasma-mass spectrometry (SP ICP-MS). The optimization of ion extraction, ion transport, and the operation of the quadrupole with increased mass bandwidth improved the signal-to-noise ratios significantly and decreased the size detection limits for all NP dispersions investigated. As a model system, 10.9 ± 1.0 nm Au NPs were analyzed to demonstrate the effects of increasing ion transmission. Specifically, increasing the mass bandwidth of the quadrupole improved the size detection limit to 4.2 nm and enabled the resolution of NP signals from ionic background and noise. Subsequently, the methods were applied to the characterization of lanthanide-doped upconversion nanoparticles (UCNPs) by SP ICP-MS. Three different types of UCNPs (90 nm NaYF4: 20% Yb, 2% Er; 20 nm NaGdF4: 20% Yb, 1% Er; 15 nm NaYF4: 20% Yb, 2% Er) were investigated. Y showed the best signal-to-noise ratios with optimized ion extraction and transport parameters only, whereas the signal-to-noise ratios of Gd, Er, and Yb were further improved by increasing the mass bandwidth of a quadrupole mass filter. The novel methods were suitable for detailed characterization of diluted UCNP dispersions including particle stoichiometries and size distributions. A Poisson model was further applied to assess particle-particle interactions in the aqueous dispersions. The methods have considerable potential for the characterization of small-diameter and/or low-mass-fraction nanoparticles.

Copyright © 2020 American Chemical Society. Lanthanide ion doped upconversion nanoparticles (UCNPs) hold great promise as multimodal contrast agents for a range of medical imaging techniques, including optical bioimaging (OBI), magnetic resonance imaging (MRI), and computed tomography (CT). However, it is challenging to obtain UCNPs with both maximal contrast enhancement effects for both OBI and MRI simultaneously owing to the dilemma in the size of UCNPs. UCNPs in large dimensions contain more photonic Ln ions and less surface defects, which is favored for high luminescent emissions, while small UCNPs with high specific surface areas allow a higher proportion of paramagnetic Ln ions to be more accessible to water molecules, which offers enhanced contrast in MRI. In this work, we report the novel design of core-porous shell UCNPs with both high luminescent emissions and magnetic relaxivities as potential dual-modal contrast agents. The core-porous shell UCNPs were fabricated via the selective etching of the inert shell of NaYF4: 30%Gd at the active core of NaYF4: 20%Yb, 1%Er. Their morphology and composition were carefully characterized using transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, X-ray diffraction, and high resolution TEM. Their photoluminescent and magnetic resonance properties were experimentally determined and compared for the core, core-dense shell, and core-porous shell UCNPs. Core-porous shell UCNPs were found to display bright luminescence and superior MRI contrast enhancement, thus showing great potential as bimodal OBI and MRI contrast agents.

Human zinc deficiency increases susceptibility to bacterial infection. Although zinc supplementation therapies can reduce the impact of disease, the molecular basis for protection remains unclear. Streptococcus pneumoniae is a major cause of bacterial pneumonia, which is prevalent in regions of zinc deficiency. We report that dietary zinc levels dictate the outcome of S. pneumoniae infection in a murine model. Dietary zinc restriction impacts murine tissue zinc levels with distribution post-infection altered, and S. pneumoniae virulence and infection enhanced. Although the activation and infiltration of murine phagocytic cells was not affected by zinc restriction, their efficacy of bacterial control was compromised. S. pneumoniae was shown to be highly sensitive to zinc intoxication, with this process impaired in zinc restricted mice and isolated phagocytic cells. Collectively, these data show how dietary zinc deficiency increases sensitivity to S. pneumoniae infection while revealing a role for zinc as a component of host antimicrobial defences.

© The Royal Society of Chemistry 2019. Standard preparation for elemental bio-imaging by laser ablation-inductively coupled plasma-mass spectrometry is confounded by the chemical and physical differences between standard and sample matrices. These differences lead to variable ablation, aerosol generation and transportation characteristics and must be considered when designing matrix-matched standards for reliable calibration and quantification. The ability to precisely mimic sample matrices is hampered due to the complexity and heterogeneity of biological tissue and small variabilities in standard matrices and sample composition often negatively impact accuracy, precision and robustness. Furthermore, cumbersome preparation protocols may limit reproducibility and traceability. This work presents novel facile methods for the preparation of gelatine standards using both commercial and laboratory-made moulds. Surface roughness, thickness and robustness of the mould-prepared standards were compared against cryo-sectioned gelatine and homogenised brain tissue standards. The mould-prepared standards had excellent thickness accuracy and signal precision which allowed robust quantification, were easier to prepare and therefore easier to reproduce. We also compared gelatine standards prepared from a variety of animal sources and discuss their suitability to calibrate low level elemental concentrations. Finally, we present a simple method to remove background metals in gelatine using various chelating resins to increase the dynamic calibration range and to improve limits of analysis.

© 2019 Eijkelkamp et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Human zinc deficiency increases susceptibility to bacterial infection. Although zinc supplementation therapies can reduce the impact of disease, the molecular basis for protection remains unclear. Streptococcus pneumoniae is a major cause of bacterial pneumonia, which is prevalent in regions of zinc deficiency. We report that dietary zinc levels dictate the outcome of S. pneumoniae infection in a murine model. Dietary zinc restriction impacts murine tissue zinc levels with distribution post-infection altered, and S. pneumoniae virulence and infection enhanced. Although the activation and infiltration of murine phagocytic cells was not affected by zinc restriction, their efficacy of bacterial control was compromised. S. pneumoniae was shown to be highly sensitive to zinc intoxication, with this process impaired in zinc restricted mice and isolated phagocytic cells. Collectively, these data show how dietary zinc deficiency increases sensitivity to S. pneumoniae infection while revealing a role for zinc as a component of host antimicrobial defences.

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. This study presents a novel size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) method for the characterisation and quantification of immunoassays with lanthanide-labelled antibodies. SEC-ICP-MS in combination with a double isotope dilution approach enabled facile validation of the antibodies’ integrity, the determination of the batch to batch labelling efficiency, monitoring of each labelling step, and quantification of the immunocomplexes after incubation with the target protein. The addition of oxygen into the dynamic reaction cell improved the detection of sulphur as a marker for the antibodies and target protein via mass-shifting (LOD = 3.7 ng/mL), whilst maintaining sufficient sensitivity for the analysis of the lanthanides. Ultra-high performance liquid chromatography (UHPLC) SEC ensured a rapid chromatographic method with separation times under 7 min of the labelled and unlabelled antibodies, the immunocomplexes, and the unconjugated polymer used to lanthanide-label the antibodies. SEC calibration estimated the molecular weights of all peaks and provided valuable insights in immunochemical reactions and the stoichiometry of the reactants and products. A novel on-line isotope dilution analysis (IDA) enabled absolute quantification of sulphur and lanthanide signals and the protein of interest. The chromatographic separation of immunocomplexes and labelled antibodies allowed the simultaneous determination of the antibody/metal stoichiometry and target protein concentration from a single mass flow chromatogram. An immunoglobulin protein was quantified after incubation with an 153Eu-labelled primary polyclonal antibody. The procedure was validated with direct labelling of the target protein with 156Gd for parallel, simultaneous quantification. The concentration determined via direct labelling of the protein deviated 1.9% from the immunochemical approach employing 15

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. MMP-11 is a member of the matrix metalloproteinase family (MMPs) which are overexpressed in cancer cells, stromal cells and the adjacent microenvironment. The MMP protein family encompasses zinc-dependent endopeptidases that degrade the extracellular matrix (ECM), facilitating the breakdown of the basal membrane and matrix connective tissues. This function is believed to be important in cancer development and metastasis. This paper investigated a gold nanoparticle-based immunohistochemical assay to visualise the distribution of MMP-11 in human breast cancer tissues from eight patients with and without metastases by employing laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The expression of MMP-11 was increased and more heterogeneous in metastatic specimens compared to non-metastatic tumour samples. These findings demonstrate that imaging breast tumours by LA-ICP-MS may be a useful tool to aid the prognosis and treatment of breast cancer. As an example, samples of two patients are presented who were diagnosed with matching characteristics and grades of breast cancer. Although both patients had a similar prognosis and treatment, only one developed metastases.

© 2017 The biological function of minor and trace elements is ordinarily determined by their association with specific proteins, peptides and other biomolecules. Therefore, measuring the total elemental content of a biological sample provides limited information, particularly when a specific effect is due to an individual metal-protein complex. Speciation of metalloproteins, heteroatom-containing molecules or other compounds tagged with an exogenous metal can be used to overcome this limitation. A range of chromatographic separation techniques with on-line elemental detection using inductively coupled plasma-mass spectrometry (ICP-MS) have been applied to the biosciences, and each technique has intrinsic features that must be considered when designing speciation experiments. This tutorial review provides an overview of speciation in the biosciences, highlighting the unique abilities and limitations encountered. A selection of recent technical advances and new applications, the challenges of sample preparation and implementation of new technical developments are discussed, as well as the future directions of technology that is rapidly gaining a foothold in the contemporary biochemistry laboratory.

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Diagnosis and localization of bacterial infections remains a significant clinical challenge. Harnessing bacteria-specific metabolic pathways, such as the maltodextrin transport mechanism, may allow specific localization and imaging of small or hidden colonies. This requires that the intrabacterial tracer accumulation provided by the transporter is matched by high serum stability of the tracer molecule. Herein, radiolabeled maltodextrins of varying chain lengths and with free nonreducing/reducing ends are reported and their behavior against starch-degrading enzymes in the blood, which compromise their serum stability, is evaluated. Successful single-photon emission computed tomography (SPECT) imaging is shown in a footpad infection model in vivo by using the newly developed model tracer, [99mTc]MB1143, and the signal is compared with that of 18F-fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) as a nonbacterial specific marker for inflammation. Although the [99mTc]MB1143 imaging signal is highly specific, it is low, most probably due to insufficient serum stability of the tracer. A series of stability tests with different 18F-labeled maltodextrins finally yielded clear structural guidelines regarding substitution patterns and chain lengths of maltodextrin-based tracers for nuclear imaging of bacterial infections.

© 2017 Elsevier B.V. Technetium (Tc) and Gadolinium (Gd) are the two most widely used metals in diagnostic medicine for scintigraphies and magnet resonance imaging (MRI), respectively. They play a crucial role for the generation or enhancement of contrast and are indispensable in countless diagnostic applications. However, the use of such contrast agents has caused severe health issues and environmental anomalies. This review aims to point out current issues and developments regarding the role and the analysis of these trace metals in medicine and the environment. Basic principles, issues and state of art of analytical methodologies are summarized. Current and future trends and the suggested implementation of novel methodologies and instrumentation are presented.

© 2017 Elsevier GmbH A novel quantification method named isobaric dilution analysis (IBDA) is introduced for internal calibration using inductively coupled plasma mass spectrometry (ICP-MS). Unlike isotope dilution analysis (IDA), where a sample to be analysed for a target analyte element is spiked with an isotopically enriched solution of the same element, IBDA uses the fact that conventional mass analysers cannot distinguish between two isobaric isotopes of different elements. Therefore, in IBDA, the sample with the element of interest is spiked with a solution of a different element, which shares at least one isobaric isotope and shows similar chemical properties resulting in a similar response. This method offers a less expensive alternative to conventional IDA especially for long-lived radionuclides of elements for which a spiking element that fulfils the above mentioned requirements can be provided. In addition, IBDA offers the advantage of making certain metastable, sometimes monoisotopic elements accessible to internal calibration using a strategy analogous to IDA. One of the elements accessible by the new calibration strategy is technetium (Tc), which suffers from a lack of standards due to safety requirements associated with its radioactivity. In this work, the principle of IBDA is first demonstrated for a certified gadolinium standard, which was diluted with a dysprosium spike exhibiting an isobaric isotope with m/z 160. The results obtained by IBDA were compared with those obtained by a conventional IDA. The concept of IBDA was subsequently used for the determination of 99Tc in a contrast agent. Since no certified Tc standards are available, the response of 99Tc was interpolated allowing accurate determinations with an uncertainty of 1%.