Elements In Biological Tissues Research Articles

Environmental impact assessment of risk elements from railway transport with the use of pollution indices, a biotest and bioindicators

The paper evaluates the accumulation of selected risk elements in soils and biological tissues caused by railway transport. Samples of soil, pine (Pinus sylvestris L.) bark and needles, hoof fungus (Fomes fomentarius L.) and red-stemmed feathermoss (Pleurozium schreberi L.) were analyzed for the content of Cd, Cr, Cu, Ni, Pb and Zn. The samples were collected in five sites (A, B, C, D, E each separated by 500 m) covering a combined distance of around 2 km along railway tracks (Central Poland). The geo-accumulation index (I geo), single pollution index (PI), contamination factor (Cf), degree of contamination (C deg), potential ecological risk (RI), and the probability of toxicity (MERMQ) index were calculated to determine soil pollution with risk elements. Soil toxicity was assessed with the Phytotoxkit biotest which measures the inhibition of seed germination and root growth in Sorghum saccharatum L. The calculated indices and the results of the phytotoxicity biotest revealed the highest levels of contamination in the proximity of a road overpass (site D). The accumulation of risk elements in soil was strongly correlated with pollutant levels in biological tissues. Zinc was the most abundant element in biological tissues, especially in pine bark and feathermoss. Soil pollution indices, biotest results, and plant and fungus bioindicators play an important role in environmental assessments of railway transport.

Matching sensitivity to abundance: high resolution immuno-mass spectrometry imaging of lanthanide labels and endogenous elements in the murine brain

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.

Solution-based calibration strategy for laser ablation–inductively coupled plasma–mass spectrometry using desolvating nebulizer system

An additional quantification strategy using a desolvating nebulizer system (DNS) for solution-based calibration was developed. For quantitative analysis, laser ablation (LA) and DNS-generated aerosols were coupled using a “Y” connector and introduced into the inductively coupled plasma (ICP). These aerosols were also observed by scanning electron microscopy following collection on a silicon chip. Internal standards (108Ag, 64Cu, 89Y) were used to correct for the different aerosol transport efficiencies between the DNS and LA. The correlation coefficients of the calibration curves for all elements ranged from 0.9986 to 0.9999. Standard reference materials (NIST 610–616 and GBW08407-08411) were used to demonstrate the accuracy and precision of the method. The results were in good agreement with certified values, and the relative standard deviation (RSD) of most elements was <3%. The limits of detection (LODs) for 50Cr, 55Mn, 59Co, 60Ni, 66Zn, 89Y, 110Cd, 139La, 140Ce, 146Nd, 147Sm, 157Gd, 163Dy, 166Er, and 208Pb were 23, 3, 3, 19, 31, 4, 12, 0.4, 0.9, 0.1, 0.2, 2, 0.3, 0.4, and 21 ng/g, respectively, which were significantly better than those obtained by other methods. Further, this approach was applied for the analysis of multiple elements in biological tissues, and the results were in good agreement with those obtained using solution-based inductively coupled plasma–mass spectrometry (ICP-MS).

Rare earths, zirconium and hafnium distribution in coastal areas: The example of Sabella spallanzanii (Gmelin, 1791)

The Zr, Hf, Y and lanthanide (REE) distribution in biological tissues of Sabella spallanzanii and Styela plicata species collected from two harbours from the northern Sicily is studied for providing information regarding the Zr, Hf and REE uptake from the environment. Previous studies determined the fractionation of dissolved REE scavenged on binding sites onto biological surfaces. By comparing the recognised shale-normalised REE patterns of studied samples with evidence from reference data, the observed behaviour of these elements in biological tissues of Sabella spallanzanii and Styela plicata is interpreted to result from the preferential uptake of intermediate REE onto carboxylic sites. Moreover, the relationship observed between the Fe content and Zr/Hf ratio suggests that preferential Hf accumulation occurs via siderophore-like binding sites. Features of the REE bioaccumulation factors (BAF), in addition to the absolute La, Ce and Sm contents and Zr-Hf fractionation, allow definition of the different origins of studied elements in the investigated localities. Higher BAF values for La and Ce associated with larger REE contents and lower Zr/Hf values strongly suggest that the environmental REE distribution in the Termini Imerese harbour is influenced by the delivery of particles from industrial sources and power plants. On the contrary, the REE contents of biological tissues collected in the Cala tourist harbour are affected by the dust dissolution from automotive traffic. These results suggest that the geochemical behaviour of REE and Zr/Hf signature can be used in environmental studies of biological tissues for reconstructing the nature of anthropogenic contaminations.

Elemental Bio-imaging of Biological Samples by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

Abstract Trace elements play very important roles in biological organism and are closely related to many diseases. New analytical methods are urgently needed for in situ determination of trace elements in biological tissues or single cells. A method based on laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was developed here for in situ analysis. Line ablation mode was chosen and the output energy of the laser was optimized at a low fluence of less than 1 J cm −2 . Two kinds of elemental image of both a coronal section from mouse brain and single cells exposed to gold nanoparticles were obtained by the developed method. Due to the unique characteristic, such as good spatial resolution, excellent detection limit, and reasonable running cost, LA-ICP-MS will be applied widely and become a useful tool in biomedical research in the future.

Direct imaging of elemental distributions in tissue sections by laser ablation mass spectrometry

We present a strategy for imaging of elements in biological tissues using laser ablation (LA) mass spectrometry (MS), which was compared to laser ablation inductively coupled plasma (LA-ICP) MS. Both methods were adopted for quantitative imaging of elements in mouse kidney, as well as traumatic brain injury model tissue sections. MS imaging (MSI) employing LA provides quantitative data by comparing signal abundances of sodium from tissues to those obtained by imaging quantitation calibration standards of the target element applied to adjacent control tissue sections. LA-ICP MSI provided quantitative data for several essential elements in both brain and kidney tissue sections using a dried-droplet approach. Both methods were used to image a rat model of traumatic brain injury, revealing accumulations of sodium and calcium in the impact area and its peripheral regions. LA MSI is shown to be a viable option for quantitative imaging of specific elements in biological tissue sections.

High-resolution elemental mapping of human placental chorionic villi using synchrotron X-ray fluorescence spectroscopy.

The placenta is the organ that mediates transport of nutrients and waste materials between mother and fetus. Synchrotron X-ray fluorescence (SXRF) microanalysis is a tool for imaging the distribution and quantity of elements in biological tissue, which can be used to study metal transport across biological membranes. Our aims were to pilot placental biopsy specimen preparation techniques that could be integrated into an ongoing epidemiology birth cohort study without harming rates of sample acquisition. We studied the effects of fixative (formalin or glutaraldehyde) and storage duration (30days or immediate processing) on metal distribution and abundance and investigated a thaw-fixation protocol for archived specimens stored at -80°C. We measured fixative elemental composition with and without a placental biopsy via inductively coupled plasma mass spectrometry (ICP-MS) to quantify fixative-induced elemental changes. Formalin-fixed specimens showed hemolysis of erythrocytes. The glutaraldehyde-paraformaldehyde solution in HEPES buffer (GTA-HEPES) had superior anatomical preservation, avoided hemolysis, and minimized elemental loss, although some cross-linking of exogenous Zn was evident. Elemental loss from tissue stored in fixative for 1month showed variable losses (≈40% with GTA-HEPES), suggesting storage duration be controlled for. Thawing of tissue held at -80°C ina GTA-HEPES solution provided high-quality visual images and elemental images.

Effect of sample preparation techniques on the concentrations and distributions of elements in biological tissues using µSRXRF: a comparative study

Routine tissue sample preparation using chemical fixatives is known to preserve the morphology of the tissue being studied. A competitive method, cryofixation followed by freeze drying, involves no chemical agents and maintains the biological function of the tissue. The possible effects of both sample preparation techniques in terms of the distribution of bio-metals (calcium (Ca), copper (Cu) zinc (Zn), and iron (Fe) specifically) in human skin tissue samples was investigated. Micro synchrotron radiation x-ray fluorescence (μSRXRF) was used to map bio-metal distribution in epidermal and dermal layers of human skin samples from various locations of the body that have been prepared using both techniques. For Ca, Cu and Zn, there were statistically significant differences between the epidermis and dermis using the freeze drying technique (p = 0.02, p < 0.01, and p < 0.01, respectively). Also using the formalin fixed, paraffin embedded technique the levels of Ca, Cu and Zn, were significantly different between the epidermis and dermis layers (p = 0.03, p < 0.01, and p < 0.01, respectively). However, the difference in levels of Fe between the epidermis and dermis was unclear and further analysis was required. The epidermis was further divided into two sub-layers, one mainly composed of the stratum corneum and the other deeper layer, the stratum basale. It was found that the difference between the distribution of Fe in the two epidermal layers using the freeze drying technique resulted in a statistically significant difference (p = 0.012). This same region also showed a difference in Fe using the formalin fixed, paraffin embedded technique (p < 0.01). The formalin fixed, paraffin embedded technique also showed a difference between the deeper epidermal layer and the dermis (p < 0.01). It can be concluded that studies involving Ca, Cu and Zn might show similar results using both sample preparation techniques, however studies involving Fe would need more special attention.

Determination of 6 Toxic Elements in Biological Tissues by High Pressure Digestion: Inductively Coupled Plasma Mass Spectrometry

Objective: A method based on high pressure digestion andinductively coupled plasma mass spectrometry (ICP-MS) detection was establishedfor determination of arsenic, mercury, lead, cadmium, chromium and thallium inbiological tissues. Method: The samplesof hair, nails, viscera, blood, urine were digested with HNO3 and H2O2in high pressure digestion tank ; Indium was used as internal standard element,The certified GBW07601a (CRM Human Hair) was adopted as the quality control forthe whole processes. Results: Theexcellent sensitivity and reliability were demonstrated by the method ofrecovery 82% ~ 110%, RSD (n = 5) less than 5% and the linear range of 0.020ng/mL to 100 ng/mL (r &gt; 0.99). The prototype measurements are within thescope of the standard value. Standard addition recovery of the six elements is therange of 92% ~ 105%. Conclusion: Arapid, easy and accurate quantitative ICP-MS method was established fordetermination of toxic elements in the human body, which enrich the existing meansof forensic technology. At the same time, this work provide the most practicaland reliable core data for poisons metabolism and pathological study.

Application of laser microdissection ICP–MS for high resolution elemental mapping in mouse brain tissue: A comparative study with laser ablation ICP–MS

Mapping of elements in biological tissue by laser induced mass spectrometry is a fast growing analytical methodology in life sciences. This method provides a multitude of useful information of metal, nonmetal, metalloid and isotopic distribution at major, minor and trace concentration ranges, usually with a lateral resolution of 12–160µm. Selected applications in medical research require an improved lateral resolution of laser induced mass spectrometric technique at the low micrometre scale and below. The present work demonstrates the applicability of a recently developed analytical methodology – laser microdissection associated to inductively coupled plasma mass spectrometry (LMD ICP–MS) – to obtain elemental images of different solid biological samples at high lateral resolution. LMD ICP–MS images of mouse brain tissue samples stained with uranium and native are shown, and a direct comparison of LMD and laser ablation (LA) ICP–MS imaging methodologies, in terms of elemental quantification, is performed.

Laser spectrometry for multi-elemental imaging of biological tissues.

An increasing interest has arisen in research focused on metallic and organic ions that play crucial roles in both physiological and pathological metabolic processes. Current methods for the observation of trace elements in biological tissues at microscopic spatial resolution often require equipment with high complexity. We demonstrate a novel approach with an all-optical design and multi-elemental scanning imaging, which is unique among methods of elemental detection because of its full compatibility with standard optical microscopy. This approach is based on laser-induced breakdown spectroscopy (LIBS), which allows the elements in a tissue sample to be directly detected and quantified under atmospheric pressure. We successfully applied this method to murine kidneys with 10 µm resolution and a ppm-level detection limit to analyze the renal clearance of nanoparticles. These results offer new insight into the use of laser spectrometry in biomedical applications in the field of label-free elemental mapping of biological tissues.

Development of Dual Beam High Speed Doppler OFDI

This paper describes development of a high speed Doppler OFDI system for non-invasive vascular imaging. Doppler OFDI (optical frequency domain imaging) is one of the phase-resolved second generation OCT (optical coherence tomography) techniques for high resolution imaging of moving elements in biological tissues. To achieve a phase-resolved imaging, two temporally separated measurements are required. In a conventional Doppler OCT, a pair of massively oversampled successive A-lines is used to minimize de-correlation noise at the expense of significant imaging speed reduction. To minimize a de-correlation noise between targeted two measurements without suffering from significant imaging speed reduction, several methods have been developed such as an optimized scanning pattern and polarization multiplexed dual beam scanning. This research represent novel imaging technique using frequency multiplexed dual beam illumination to measure exactly same position with aimed time interval. Developed system has been verified using a tissue phantom and mouse vessel imaging.

Elemental Mapping of Cardiac Tissue by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy: Proof of Principle in Chaga's Disease Myocarditis Model

Tissue electrolytes (especially calcium, sodium, and potassium) are critical elements for proper cardiomyocyte and whole heart contractile performance. The levels of these minerals are markedly altered in cardiomyopathies.1 Energy dispersive X-ray spectroscopy (EDS) associated with scanning electron microscopes has a potential applicability to the spatial mapping and evaluation of the relative distribution of chemical elements in biological tissues, including cardiac tissue.2 Thus, a scanning electron microscope (Le01430VP; Carl Zeiss, Jena, Thuringia, Germany) with an attached X-ray detector (TracorTN5502; Middleton, WI) was used to obtain images of the distribution of chemical elements and to determine the proportion of carbon, sodium, potassium, calcium, magnesium, copper, zinc, and selenium in cardiac tissue infected by Trypanosoma cruzi.

A quantitative x-ray detection system for gold nanoparticle tumour biomarkers

X-ray fluorescence techniques have proven beneficial for identifying and quantifying trace elements in biological tissues. A novel approach is being developed that employs x-ray fluorescence with an aim to locate heavy nanoparticles, such as gold, which are embedded into tissues. Such nanoparticles can be functionalized to act as markers for tumour characteristics to map the disease state, with the future aim of imaging them to inform cancer therapy regimes. The uptake of functionalized nanoparticles by cancer cells will also enable detection of small clusters of infiltrating cancer cells which are currently missed by commonly used imaging modalities. The novel system, consisting of an energy-resolving silicon drift detector with high spectral resolution, shows potential in both quantification of and sensitivity to nanoparticle concentrations typically found in tumours. A series of synchrotron measurements are presented; a linear relationship between fluorescence intensity and gold nanoparticle (GNP) concentration was found down to 0.005 mgAu ml−1, the detection limit of the system. Successful use of a bench-top source, suitable for possible future clinical use, is also demonstrated, and found not to degrade the detection limit or accuracy of the GNP concentration measurement. The achieved system sensitivity suggests possible future clinical usefulness in measuring tumour uptake in vivo, particularly in shallow tumour sites and small animals, in ex vivo tissue and in 3D in vitro research samples.

Laser ablation ICP-MS for quantitative biomedical applications

LA-ICP-MS allows precise, relatively fast, and spatially resolved measurements of elements and isotope ratios at trace and ultratrace concentration levels with minimal sample preparation. Over the past few years this technique has undergone rapid development, and it has been increasingly applied in many different fields, including biological and medical research. The analysis of essential, toxic, and therapeutic metals, metalloids, and nonmetals in biomedical tissues is a key task in the life sciences today, and LA-ICP-MS has proven to be an excellent complement to the organic MS techniques that are much more commonly employed in the biomedical field. In order to provide an appraisal of the fast progress that is occurring in this field, this review critically describes new developments for LA-ICP-MS as well as the most important applications of LA-ICP-MS, with particular emphasis placed on the quantitative imaging of elements in biological tissues, the analysis of heteroatom-tagged proteins after their separation and purification by gel electrophoresis, and the analysis of proteins that do not naturally have ICP-MS-detectable elements in their structures, thus necessitating the use of labelling strategies.

Early Stiffening and Softening of Collagen: Interplay of Deformation Mechanisms in Biopolymer Networks

Collagen networks, the main structural/mechanical elements in biological tissues, increasingly serve as biomimetic scaffolds for cell behavioral studies, assays, and tissue engineering, and yet their full spectrum of nonlinear behavior remains unclear. Here, with self-assembled type-I collagen as model, we use metrics beyond those in standard single-harmonic analysis of rheological measurements to reveal strain-softening and strain-stiffening of collagen networks both in instantaneous responses and at steady state. The results show how different deformation mechanisms, such as deformation-induced increase in the elastically active fibrils, nonlinear extension of individual fibrils, and slips in the physical cross-links in the network, can lead to the observed complex nonlinearity. We demonstrate how comprehensive rheological analyses can uncover the rich mechanical properties of biopolymer networks, including the above-mentioned softening as well as an early strain-stiffening, which are important for understanding physiological response of biological materials to mechanical loading.

Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod (Porcellio scaber, Isopoda, Crustacea)

Micro-proton induced X-ray emission (micro-PIXE) method was applied to study the micro-localization of silver (Ag) in digestive glands of a terrestrial arthropod (Porcellio scaber) after feeding on silver nanoparticles (nano-Ag) dosed food. The aim of our work was to assess whether feeding on nano-Ag results in the assimilation of silver (Ag) in digestive gland cells. To study micro-localization and elemental distribution of Ag, the animals were fed on food dosed with nanoparticles for 14days under controlled laboratory conditions. At the end of the feeding exposure, the animals were dissected and digestive glands prepared for micro-PIXE analyses and TEM investigation. The results obtained by micro-PIXE documented high amounts of Ag inside S-cells of the digestive gland epithelium; however, TEM investigation did not show particle aggregates inside digestive gland cells. Also no adverse effect on feeding behavior was recorded what is a measure of toxic effects. We explain the presence of Ag inside the cells as a result of the assimilation of dissoluted Ag ions from ingested nano-Ag particles. Assimilation of excessive amounts of ingested metal ions in S-cells is a well known metal detoxification mechanism in isopods. We discuss the advantages of using micro-PIXE for the micro-localization of elements in biological tissue in studies of interactions between nanoparticles and biological systems.

Mass spectrometric imaging of elements in biological tissues by new BrainMet technique—laser microdissection inductively coupled plasma mass spectrometry (LMD-ICP-MS)

Bioimaging of elements in biological tissues is a fast growing technology in the life sciences since it provides direct information on the metal distribution which is involved in metabolism in all kinds of organisms. In the present study, we proposed a novel mass spectrometric imaging technique, laser microdissection inductively coupled plasma mass spectrometry (LMD-ICP-MS), which is intended to investigate elemental distribution in small areas of biological tissue with high spatial resolution down to the low-micrometre range and below. The LMD-ICP-MS technique combines a laser microdissection apparatus (LMD) with sensitive quadrupole-based inductively coupled plasma mass spectrometry (ICP-QMS) to utilize the tightly focused laser beam in LMD for the ablation of sample materials which then are analyzed by ICP-QMS. The laser beam with a 1 μm spot diameter was used to ablate the material from a Cu-spiked brain tissue slice, and corresponding ion intensities of elements of interest (for instance, 13C+ and 63Cu+) were observed by ICP-QMS along the scan. First images of metals and selected non-metals were obtained using the new LMD-ICP-MS imaging technique on small regions of the brain standard slice. Inhomogeneous distribution of the materials (via the image of 13C+) and elements (via the images of 23Na+, 24Mg+, 31P+, 56Fe+, 63Cu+, 64Zn+) in the scanned regions was revealed by LMD-ICP-MS imaging with a spatial resolution of 30 μm, 15 μm, and 8 μm, respectively. Additionally, images of P, Mg, K and Fe with a lateral resolution of 4 μm in a region of a mouse brain slice were obtained by imaging LMD-ICP-MS. Quantification in LMD-ICP-MS was possible via calibration curves generated by a set of synthetic brain standards similar to the procedure in laser ablation ICP-MS. Further studies with respect to the performance of LMD-ICP-MS and the optimization of experimental parameters when using laser beams with smaller spot sizes in LMD will be carried out in developing the LMD-ICP-MS imaging technique.

Imaging of essential and toxic elements in biological tissues by LA-ICP-MS

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) using double-focusing sector field (LA-ICP-SFMS) or quadrupole-based mass spectrometers (LA-ICP-QMS) was employed as powerful imaging (mapping) techniques to produce images of detailed regionally specific element distributions in thin tissue sections of different sizes such as control rat brain tissues or tumor regions to study tumor growing. LA-ICP-QMS was employed to investigate the uptake and the transport of nutrient elements in plant tissues or imaging of metals in proteins separated by native 2D BN-PAGE.

Leaching of Trace Elements from Biological Tissue by Formalin Fixation

In studies of trace elements in biological tissue, it is imperative that sample handling does not substantially change element concentrations. In many cases, fresh tissue is not available for study, but formalin-fixed tissue is. Formalin fixation has the potential to leach elements from the tissue, but few studies have been published in this area. The concentrations of 19 elements were determined by high-resolution inductively coupled plasma mass spectrometry in formalin in which human and rat brain samples had been stored for different time durations ranging from weeks up to several years. Additional analysis was carried out in fixed brain samples. There was substantial leaching of elements from the tissue into the formalin, and the leaching varied considerably between different elements. For example, formalin concentrations of As, Cd, Mg, Rb, and Sb increased more than 100-fold upon long-term (years) storage, while for Ni and Cr, the leaching was negligible. The degree of leaching was strongly time-dependent. In conclusion, formalin fixation and storage of biological tissue has the potential to leach substantial fractions of several trace elements from the tissue. The potential of leaching must be critically considered when using formalin-fixed biological tissue in trace metal analysis.