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Plant nanobiotechnology has the potential to revolutionize agriculture. However, the lack of effective methods to deliver nanoparticles (NPs) to the precise locations in plants where they are needed impedes these technological innovations. Here, model gold nanoparticles (AuNP) were coated with citrate, bovine serum albumin (BSA) as a protein control, or LM6-M, an antibody with an affinity for functional groups unique to stomata on leaf surfaces to deliver the AuNPs to stomata. One-month-old Vicia faba leaves were exposed via drop deposition to aqueous suspensions of LM6-M-coated AuNPs and allowed to air dry. After rinsing, Au distribution on the leaf surface was investigated by enhanced dark-field microscopy and X-ray fluorescence mapping. While citrate-coated AuNPs randomly covered the plant leaves, LM6M-AuNPs strongly adhered to the stomata and remained on the leaf surface after rinsing, and BSA-AuNPs specifically targeted trichome hairs. To the authors' knowledge, this is the first report of active targeting of live leaf structures using NPs coated with molecular recognition molecules. This proof-of-concept study provides a strategy for future targeted nanopesticide delivery research.

Numerous studies have documented rare-earth element (REE) mobility in hydrothermal and metamorphic fluids, but the processes and timing of REE mobility are rarely well constrained. The Round Top laccolith in the Trans-Pecos magmatic province of west Texas, a REE ore prospect, has crosscutting fractures filled with fluorite and calcite along with a variety of unusual minerals. Most notably among these is an yttrium and heavy rare-earth element (YHREE) carbonate mineral, which is hypothesized to be lokkaite based on elemental analyses. While the Round Top laccolith is dated to 36.2 ± 0.6 Ma based on K/Ar in biotite, U-Pb fluorite and nacrite ages presented here clearly show the mineralization in these veins is younger than 6.2 ± 0.4 Ma (the age of the oldest fluorite). This discrepancy in dates suggests that fluids interacted with the laccolith to mobilize REE more than 30 m.y. after igneous emplacement. The timing of observed REE mobilization overlaps with Rio Grande rift extension, and we suggest that F-bearing fluids associated with extension may be responsible for initial mobilization. A later generation of fluids was able to dissolve fluorite, and we hypothesize this later history involved sulfuric acid. Synchrotron spectroscopy and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) U-Pb dating of minerals that record these fluids offer tremendous potential for a more fundamental understanding of processes that are important not only for REE but other ore deposits as well.

Soils regulate the environmental impacts of trace elements, but direct measurements of reaction mechanisms in these complex, multi-component systems can be challenging. The objective of this work was to develop approaches for assessing effects of co-localized geochemical matrix elements on the accumulation and chemical speciation of arsenate applied to a soil matrix. Synchrotron X-ray fluorescence microprobe (µ-XRF) images collected across 100 µm × 100 µm and 10 µm × 10 µm regions of a naturally weathered soil sand-grain coating before and after treatment with As(V) solution showed strong positive partial correlations (r′ = 0.77 and 0.64, respectively) between accumulated As and soil Fe, with weaker partial correlations (r′ > 0.1) between As and Ca, and As and Zn in the larger image. Spatial and non-spatial regression models revealed a dominant contribution of Fe and minor contributions of Ca and Ti in predicting accumulated As, depending on the size of the sample area analyzed. Time-of-flight secondary ion mass spectrometry analysis of an area of the sand grain showed a significant correlation (r = 0.51) between Fe and Al, so effects of Fe versus Al (hydr)oxides on accumulated As could not be separated. Fitting results from 25 As K-edge microscale X-ray absorption near-edge structure (µ-XANES) spectra collected across a separate 10 µm × 10 µm region showed ∼60% variation in proportions of Fe(III) and Al(III)-bound As(V) standards, and fits to µ-XANES spectra collected across the 100 µm × 100 µm region were more variable. Consistent with insights from studies on model systems, the results obtained here indicate a dominance of Fe and possibly Al (hydr)oxides in controlling As(V) accumulation within microsites of the soil matrix analyzed, but the analyses inferred minor augmentation from co-localized Ti, Ca and possibly Zn.

Root uptake and translocation of engineered nanoparticles (NPs) by plants are dependent on both plant species and NP physicochemical properties. To evaluate the influence of NP surface charge and differences in root structure and vasculature on cerium distribution and spatial distribution within plants, two monocotyledons (corn and rice) and two dicotyledons (tomato and lettuce) were exposed hydroponically to positively-charged, negatively-charged, and neutral ∼4 nm CeO2 NPs. Leaves were analyzed using synchrotron-based X-ray fluorescence microscopy to provide lateral Ce spatial distribution. Surface charge mediated CeO2 NP interactions with roots for all plant species. Positively charged CeO2 NPs associated to the roots more than the negatively charged NPs due to electrostatic attraction/repulsion to the negatively charged root surfaces, with the highest association for the tomato, likely due to higher root surface area. The positive NPs remained primarily adhered to the roots untransformed, while the neutral and negative NPs were more efficiently translocated from the roots to shoots. This translocation efficiency was highest for the tomato and lettuce compared to corn and rice. Across all plant species, the positive and neutral treatments resulted in the formation of Ce clusters outside of the main vasculature in the mesophyll, while the negative treatment resulted in Ce primarily in the main vasculature of the leaves. Comparing leaf vasculature, Ce was able to move much further outside of the main vasculature in the dicot plants than monocot plants, likely due to the larger airspace volume in dicot leaves compared to monocot leaves. These results provide valuable insight into the influence of plant structure and NP properties on metal transport and distribution of NPs in plants.

Using recent advances in X-ray microscopy, this study aimed to elucidate mechanisms of uptake, subcellular distribution, and translocation of functionalized CeO2 MNM (manufactured nanomaterials), having different charges, by tomato plants (Solanum lycopersicum cv Micro-Tom). We found that plant growth and Ce concentration in tissues were functions of surface charge and exposure concentration with root to shoot translocation being much greater for negatively charged CeO2 than positive or neutral CeO2. Mechanisms of entry into roots and translocation within plants were examined using X-ray nano- and microprobes. There were dramatic differences in the tissue and subcellular distributions of Ce in plant roots exposed to dextran-coated CeO2 nanoparticles conjugated with positive, neutral and negative functional groups. Positively charged CeO2 remained mainly bound to the epidermis of the root with little present in the apoplast or cytoplasm. Negatively charged CeO2 was found in the cytoplasm throughout the root cross section, and negatively charged CeO2 was found within the apoplast in the cortex and both the apoplast and the cytoplasm in the vasculature. Neutral CeO2 likely entered through the gaps between epidermal cells being sloughed off during root growth and penetrated deeper into the interior of the roots (vasculature) via a combination of apoplastic and symplastic transport. Evidence of symplastic Ce transport was observed with the neutrally and negatively charged particles. We observed evidence of endocytosis as the mechanism for entry into the symplast allowing for entry into the xylem. This study provides critical information on how particle surface chemistry influences the biodistribution and cellular localization of nanomaterials in plants and is to date the highest resolution X-ray imaging of nanomaterials in plant cells.

Scientists have long suspected that compositionally zoned particles can form under far-from equilibrium precipitation conditions, but their inferences have been based on bulk solid and solution measurements. We are the first to directly observe nanoscale trace element compositional zonation in 4) particles precipitated from aqueous solution, in which Sr2+ cations as well as HAsO42− anions were co-precipitated into (Ba,Sr)SO4 or Ba(SO4,HAsO4) solid solutions. Under high salinity conditions (NaCl ≥ 1.0 M), bands contained ~3.5 to ~5 times more trace element compared to the center of the particle formed in early stages of particle growth. Quantitative analysis of Sr and As fractional substitution allowed us to determine that different crystallographic growth directions incorporated trace elements to different extents. These findings provide supporting evidence that barite solid solutions have great potential for trace element incorporation; this has significant implications for environmental and engineered systems that remove hazardous substances from water.

Of late, many synthesis processes have been studied to develop irregular nano-morphologies of gold nanostructures for biomedical applications in order to increase the efficacy of nanoparticle theranostics, tune the plasmonic absorbance spectra, and increase the sensitivity of biomolecule detection through surface enhanced Raman spectroscopy. Here we report, a novel, non-seed mediated versatile single pot synthesis method capable of producing hyperbranched gold “nano-polyvilli” with more than 50–90 branching nanowires propagating from a single origin within each structure. The technique was capable of achieving precise tuning of the branch propagation where the branching could be controlled by varying the duration of incubation, temperature, and hydrogen ion concentration.

The international user base of the Cornell High Energy Synchrotron Source (CHESS) gathered in Ithaca, NY, from June 10–11, 2014, for the annual CHESS Users' Meeting and affiliated workshops. This year drew a record crowd of 174 participants from diverse disciplines in academia and industry to celebrate the outstanding achievements of CHESS users over the past year and to discuss the ongoing upgrades of the facility and the new science that they will enable. As per tradition, the first day of the meeting was a plenary session, which began with a morning briefing from the CHESS directors on the state of the laboratory. This was followed by a series of invited talks in user science, with subject matter spanning the multidisciplinary spectrum of CHESS research, from virology to superconductivity to art conservation. These plenary sessions preceded a well-attended poster session and wine-and-cheese reception, where more than 50 user posters were up for discussion. The evening was capped off with a banquet dinn...

Sclerostin antibody (Scl-Ab) is a novel bone-forming agent that is currently undergoing preclinical and clinical testing. Scl-Ab treatment is known to dramatically increase bone mass, but little is known about the quality of the bone formed during treatment. In the current study, global mineralization of bone matrix in rats and nonhuman primates treated with vehicle or Scl-Ab was assayed by backscattered scanning electron microscopy (bSEM) to quantify the bone mineral density distribution (BMDD). Additionally, fluorochrome labeling allowed tissue age–specific measurements to be made in the primate model with Fourier-transform infrared microspectroscopy to determine the kinetics of mineralization, carbonate substitution, crystallinity, and collagen cross-linking. Despite up to 54% increases in the bone volume after Scl-Ab treatment, the mean global mineralization of trabecular and cortical bone was unaffected in both animal models investigated. However, there were two subtle changes in the BMDD after Scl-Ab treatment in the primate trabecular bone, including an increase in the number of pixels with a low mineralization value (Z5) and a decrease in the standard deviation of the distribution. Tissue age–specific measurements in the primate model showed that Scl-Ab treatment did not affect the mineral-to-matrix ratio, crystallinity, or collagen cross-linking in the endocortical, intracortical, or trabecular compartments. Scl-Ab treatment was associated with a nonsignificant trend toward accelerated mineralization intracortically and a nearly 10% increase in carbonate substitution for tissue older than 2 weeks in the trabecular compartment (p

The G171V mutation in the low-density lipoprotein receptor-related protein 5 (LRP5) leads to a high bone mass (HBM) phenotype. Studies using HBM transgenic mouse models have consistently found increased bone mass and whole-bone strength, but little attention has been paid to the composition of the bone matrix. The current study sought to determine if the cortical bone matrix composition differs in HBM and wild-type mice and to determine how much of the variance in bone material properties is explained by variance in matrix composition. Consistent with previous studies, HBM mice had greater cortical area, moment of inertia, ultimate force, bending stiffness, and energy to failure than wild-type animals. The increased energy to failure was primarily caused by a large increase in post-yield behavior, with no difference in pre-yield behavior. The HBM mice had increased mineral-to-matrix and collagen cross-link ratios, and decreased crystallinity, carbonate, and acid phosphate substitution as measured by Fourier transform infrared microspectroscopy, but no differences in crystal length, intra-fibular strains, and mineral spacing compared to wild-type controls, as measured by X-ray scattering. The largest between genotype difference in material properties was a twofold increase in the modulus of toughness in HBM mice. Step-wise regression analyses showed that the specific matrix compositional parameters most closely associated with material properties varied between the wild-type and HBM genotypes. Although the mechanisms controlling the paradoxical combination of more mineralized yet tougher bone in HBM mice remain to be fully explained, the findings suggest that LRP5 represents a target to not only build bone mass but also to improve bone quality.

Fourier transform infrared microspectroscopy (FTIRM) is a widely used method for mapping the material properties of bone and other mineralized tissues, including mineralization, crystallinity, carbonate substitution, and collagen cross-linking. This technique is traditionally performed in a transmission-based geometry, which requires the preparation of plastic-embedded thin sections, limiting its functionality. Here, we theoretically and empirically demonstrate the development of reflection-based FTIRM as an alternative to the widely adopted transmission-based FTIRM, which reduces specimen preparation time and broadens the range of specimens that can be imaged. In this study, mature mouse femurs were plastic-embedded and longitudinal sections were cut at a thickness of 4 μm for transmission-based FTIRM measurements. The remaining bone blocks were polished for specular reflectance-based FTIRM measurements on regions immediately adjacent to the transmission sections. Kramers-Kronig analysis of the reflectance data yielded the dielectric response from which the absorption coefficients were directly determined. The reflectance-derived absorbance was validated empirically using the transmission spectra from the thin sections. The spectral assignments for mineralization, carbonate substitution, and collagen cross-linking were indistinguishable in transmission and reflection geometries, while the stoichiometric/nonstoichiometric apatite crystallinity parameter shifted from 1032/1021 cm(-1) in transmission-based to 1035/1025 cm(-1) in reflection-based data. This theoretical demonstration and empirical validation of reflection-based FTIRM eliminates the need for thin sections of bone and more readily facilitates direct correlations with other methods such as nanoindentation and quantitative backscatter electron imaging (qBSE) from the same specimen. It provides a unique framework for correlating bone's material and mechanical properties.

Bone’s microporosities play important biologic and mechanical roles. Here, we quantified 3D changes in cortical osteocyte-lacunae and other small porosities induced by estrogen withdrawal and two different osteoporosis treatments. Unlike 2D measurements, these data collected via synchrotron radiation-based μCT describe the size and 3D spatial distribution of a large number of porous structures. Six-month old female Sprague-Dawley rats were separated into four groups of age-matched controls, untreated OVX, OVX treated with PTH, and OVX treated with Alendronate (ALN). Intracortical microporosity of the medial quadrant of the femoral diaphysis was quantified at endosteal, intracortical, and periosteal regions of the samples, allowing the quantification of osteocyte lacunae that were formed primarily before versus after the start of treatment. Across the overall thickness of the medial cortex, lacunar volume fraction (Lc.V/TV) was significantly lower in ALN treated rats compared to PTH. In the endosteal region, average osteocyte lacunar volume () of untreated OVX rats was significantly lower than in age-matched controls, indicating a decrease in osteocyte lacunar size in bone formed on the endosteal surface after estrogen withdrawal. The effect of treatment (OVX, ALN, PTH) on the number of lacunae per tissue volume (Lc.N/TV) was dependent on the specific location within the cortex (endosteal, intracortical, periosteal). In both the endosteal and intracortical regions, Lc.N/TV was significantly lower in ALN than in untreated OVX, suggesting a site-specific effect in osteocyte lacuna density with ALN treatment. There also were a significantly greater number of small pores (5–100 μm3 in volume) in the endosteal region for PTH compared to ALN. The mechanical impact of this altered microporosity structure is unknown, but might serve to enhance, rather than deteriorate bone strength with PTH treatment, as smaller osteocyte lacunae may be better able to absorb shear forces than larger lacunae. Together, these data demonstrate that current treatments of osteoporosis can alter the number, size, and distribution of microporosities in cortical rat lamellar bone.

X-ray scattering of biological macromolecules in solution is an increasingly popular tool for structural biology and benefits greatly from modern high-brightness synchrotron sources. The upgraded MacCHESS BioSAXS station is now located at the 49-pole wiggler beamline G1. The 20-fold improved flux over the previous beamline F2 provides higher sample throughput and autonomous X-ray scattering data collection using a unique SAXS/WAXS dual detectors configuration. This setup achieves a combinedq-range from 0.007 to 0.7 Å−1, enabling better characterization of smaller molecules, while opening opportunities for emerging wide-angle scattering methods. In addition, a facility upgrade of the positron storage ring to continuous top-up mode has improved beam stability and eliminated beam drift over the course of typical BioSAXS experiments. Single exposure times have been reduced to 2 s for 3.560 mg ml−1lysozyme with an average quality factorI/σ of 20 in the Guinier region. A novel disposable plastic sample cell design that incorporates lower background X-ray window material provides users with a more pristine sample environment than previously available. Systematic comparisons of common X-ray window materials bonded to the cell have also been extended to the wide-angle regime, offering new insight into best choices for variousq-space ranges. In addition, a quantitative assessment of signal-to-noise levels has been performed on the station to allow users to estimate necessary exposure times for obtaining usable signals in the Guinier regime. Users also have access to a new BioSAXS sample preparation laboratory which houses essential wet-chemistry equipment and biophysical instrumentation. User experiments at the upgraded BioSAXS station have been on-going since commissioning of the beamline in Summer 2013. A planned upgrade of the G1 insertion device to an undulator for the Winter 2014 cycle is expected to further improve flux by an order of magnitude.

The influence of the macroscale material properties of bone on its mechanical competence has been extensively investigated, but less is known about possible contributions from bone’s nanoscale material properties. These nanoscale properties, particularly the collagen network and the size and shape of hydroxyapatite mineral crystals, may be affected by aging, mechanical loading, and diseases including osteoporosis. Here, changes to the collagen and mineral properties of cortical bone induced by osteoporosis and subsequent pharmaceutical treatments were investigated by simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS) microbeam mapping. Adult rats (6 months old) were ovariectomized and treated with alendronate, parathyroid hormone, or sodium fluoride, and compared to untreated ovariectomized and age-matched controls. Scattering data from tibial cortical bone showed that osteoporosis increased collagen alignment in existing intracortical bone, while this effect was mitigated in the alendronate and sodium fluoride groups though by different mechanisms. Further, mineral crystal lengths in newly formed cortical bone were smaller in animals with osteoporosis, but existing cortical bone was not altered. Subsequent treatment with alendronate mitigated changes in crystal lengths. Together, these results suggest that osteoporosis may alter the collagen alignment and mineral geometry in bone formed before and after the onset of this disease, and that osteoporosis treatments may differentially rescue these changes.

Sclerostin antibody (Scl-Ab) is a novel bone-forming agent that is currently undergoing preclinical and clinical testing. Scl-Ab treatment is known to dramatically increase bone mass, but little is known about the quality of the bone formed during treatment. In the current study, global mineralization of bone matrix in rats and nonhuman primates treated with vehicle or Scl-Ab was assayed by backscattered scanning electron microscopy (bSEM) to quantify the bone mineral density distribution (BMDD). Additionally, fluorochrome labeling allowed tissue age-specific measurements to be made in the primate model with Fourier-transform infrared microspectroscopy to determine the kinetics of mineralization, carbonate substitution, crystallinity, and collagen cross-linking. Despite up to 54% increases in the bone volume after Scl-Ab treatment, the mean global mineralization of trabecular and cortical bone was unaffected in both animal models investigated. However, there were two subtle changes in the BMDD after Scl-Ab treatment in the primate trabecular bone, including an increase in the number of pixels with a low mineralization value (Z5) and a decrease in the standard deviation of the distribution. Tissue age-specific measurements in the primate model showed that Scl-Ab treatment did not affect the mineral-to-matrix ratio, crystallinity, or collagen cross-linking in the endocortical, intracortical, or trabecular compartments. Scl-Ab treatment was associated with a nonsignificant trend toward accelerated mineralization intracortically and a nearly 10% increase in carbonate substitution for tissue older than 2 weeks in the trabecular compartment (p0.001). These findings suggest that Scl-Ab treatment does not negatively impact bone matrix quality.

Microspectroscopic imaging in the infrared (IR) spectral region allows for the examination of spatially resolved chemical composition on the microscale. More than a decade ago, it was demonstrated that diffraction limited spatial resolution can be achieved when an apertured, single pixel IR microscope is coupled to the high brightness of a synchrotron light source. Nowadays, many IR microscopes are equipped with multi-pixel Focal Plane Array (FPA) detectors, which dramatically improve data acquisition times for imaging large areas. Recently, progress been made toward efficiently coupling synchrotron IR beamlines to multi-pixel detectors, but they utilize expensive and highly customized optical schemes. Here we demonstrate the development and application of a simple optical configuration that can be implemented on most existing synchrotron IR beamlines in order to achieve full-field IR imaging with diffraction-limited spatial resolution. Specifically, the synchrotron radiation fan is extracted from the bending magnet and split into four beams that are combined on the sample, allowing it to fill a large section of the FPA. With this optical configuration, we are able to oversample an image by more than a factor of two, even at the shortest wavelengths, making image restoration through deconvolution algorithms possible. High chemical sensitivity, rapid acquisition times, and superior signal-to-noise characteristics of the instrument are demonstrated. The unique characteristics of this setup enabled the real time study of heterogeneous chemical dynamics with diffraction-limited spatial resolution for the first time.

Radiation rapidly undermines trabecular architecture, a destructive process which proceeds despite a devastated cell population. In addition to the 'biologically orchestrated' resorption of the matrix by osteoclasts, physicochemical processes enabled by a damaged matrix may contribute to the rapid erosion of bone quality. 8w male C57BL/6 mice exposed to 5 Gy of Cs(137) γ-irradiation were compared to age-matched control at 2d, 10d, or 8w following exposure. By 10d, irradiation had led to significant loss of trabecular bone volume fraction. Assessed by reflection-based Fourier transform infrared imaging (FTIRI), chemical composition of the irradiated matrix indicated that mineralization had diminished at 2d by -4.3±4.8%, and at 10d by -5.8±3.2%. These data suggest that irradiation facilitates the dissolution of the matrix through a change in the material itself, a conclusion supported by a 13.7±4.5% increase in the elastic modulus as measured by nanoindentation. The decline in viable cells within the marrow of irradiated mice at 2d implies that the immediate collapse of bone quality and inherent increased risk of fracture is not solely a result of an overly-active biologic process, but one fostered by alterations in the material matrix that predisposes the material to erosion.

Dentin matrix protein-1 (DMP1) is a key regulator of biomineralization. Here, we examine changes in structural, geometric, and material properties of cortical bone in a transgenic mouse model overexpressing DMP1. Micro-computed tomography and three-point bending were performed on 90 femora of wild type and transgenic mice at 1, 2, 4, and 6 months. Fourier transform infrared imaging was performed at 2 months. We found that the transgenic femurs were longer (p

Boron is found in everyday foods and drinking water in trace quantities. Boron exists as boric acid (BA) within plants and animals, where low levels have been linked to cancer incidence. However, this correlation is not well characterized. In this study, we examined the chemical and morphological effects of BA on human skin melanoma cells (SK-MEL28) using Fourier Transform InfraRed Imaging (FTIRI) with a Focal Plane Array (FPA) detector. Cells were grown under concentrations of BA ranging from 0 to 50 mM. Cell viability was determined after 1, 2, 3, 5, 7 and 10 days using trypan blue staining. With FTIRI, images of approximately twenty cells per time point per condition were collected. Principal components analysis (PCA) was used to evaluate changes in cell composition, with particular focus on the lipid, protein, and nucleic acid spectral components. Results from trypan blue staining revealed decreased cell viability as BA concentration increased. FTIRI data indicated that the protein and lipid contents (as indicated by the lipid/protein ratio) did not undergo substantial changes due to BA treatment. In contrast, the nucleic acid/protein ratio significantly decreased with BA treatment. PCA results showed an increase in beta-sheet protein at higher concentrations of BA (12.5, 25, and 50 mM). Together, these results suggest that high concentrations of BA have an anti-proliferative effect and show signs consistent with apoptosis.