Electron beam lithography (EBL) is one of the tools of choice for writing micro- and nanostructures on a wide variety of materials. This is largely due to the fact that modern EBL machines are ...capable of writing nanometer-sized structures on areas up to
mm
2
. The aim of this contribution is to give technical and practical backgrounds in this extremely flexible nanofabrication technique.
Nanorods standing at attention! A self‐assembly technique based on convective and capillary forces was used for the direct fabrication of standing arrays of gold nanorods on lithographically ...predefined areas (see picture). The hexagonal close‐packed structure of gold nanorods creates an ideal substrate for surface‐enhanced Raman spectroscopy.
The evaluation of nanomaterials intracellular distribution still remains a challenge in nanomedicine applications and toxicological studies. Synchrotron radiation X‐ray microscopy combined with X‐ray ...fluorescence (XRF) microspectroscopy provides unique information that has pushed the frontiers of biological research, particularly when investigating intracellular mechanisms. In this work, the presence of silica nanoparticles in in vitro cultured human lung epithelial cell line and freshly extract human monocytes has been investigated. For the uptake and intracellular distribution of NPs, cells were cultured on polymeric substrates (Mylar). The SiO2–NPs have been synthesized at JRC and characterized by dynamic light scattering, centrifugal liquid sedimentation, and transmission electron microscopy (TEM), whereas their interaction with cells was investigated with TEM and XRF. For the latter, we used TwinMic in scanning transmission mode coupled with low‐energy XRF spectroscopy, paying particular attention to the distribution of different elements, namely, Fe, O, C, Si, and Mg. Si XRF signals recorded on cells exposed to uncoated silica and epoxy‐coated silica nanoparticles are comparable, indicating low difference in cellular uptake and suggesting a similar interaction between nanoparticles and cells. However, the TEM analysis indicates a better affinity of the coated nanoparticles for the cell membrane. Moreover, the TEM analysis shows also the presence of nanoparticles in endosomes.
The current status of the TwinMic beamline at Elettra synchrotron light source, that hosts the European twin X‐ray microscopy station, is reported. The X‐ray source, provided by a short hybrid ...undulator with source size and divergence intermediate between bending magnets and conventional undulators, is energy‐tailored using a collimated plane‐grating monochromator. The TwinMic spectromicroscopy experimental station combines scanning and full‐field imaging in a single instrument, with contrast modes such as absorption, differential phase, interference and darkfield. The implementation of coherent diffractive imaging modalities and ptychography is ongoing. Typically, scanning transmission X‐ray microscopy images are simultaneously collected in transmission and differential phase contrast and can be complemented by chemical and elemental analysis using across‐absorption‐edge imaging, X‐ray absorption near‐edge structure or low‐energy X‐ray fluorescence. The lateral resolutions depend on the particular imaging and contrast mode chosen. The TwinMic range of applications covers diverse research fields such as biology, biochemistry, medicine, pharmacology, environment, geochemistry, food, agriculture and materials science. They will be illustrated in the paper with representative results.
A detailed description of the TwinMic beamline installed at Elettra, Italy, is presented. The beamline hosts a unique soft X‐ray microscope supporting both transmission and scanning X‐ray microscopy (TXM and STXM, respectively) within the one instrument. The beamline presently fosters the following techniques: STXM, TXM and ptychography, that can be combined with low‐energy X‐ray fluorescence and X‐ray absorption near‐edge structure spectroscopies. A detailed update of the design, operational modes and future upgrades of the TwinMic beamline is presented.
The amyloid precursor protein (APP) gene family includes APP and the amyloid precursor-like proteins, APLP1 and APLP2. These proteins contain metal binding sites for copper, zinc and iron and are ...known to have physiological roles in modulating the metal homeostasis in brain cells. Here we report the application of X-ray fluorescence microscopy (XFM) to investigate the subcellular distribution patterns of the metal ions Cu, Zn, Fe, and Ca in individual neurons derived from APP and APLP2 knockout mice brains to further define their role in metal homeostasis. These studies add to the growing body of data that the APP family of proteins are metalloproteins that have shared as well as distinct effects on metals. As we continue to delineate the cellular effects of the APP family of proteins it is important to consider how metals are involved in their actions.
The fabrication of single electron transistors and/or highly sensitive biosensors is still a challenging task on account of the tight control required to get proper shapes and size of the electrodes. ...The nanosized tips and the separation of a few nanometers between electrode pairs are critical features. Conventional lithography is not suited to obtain these features because of the resolution limits, so that previous alternative approaches have involved the use of electron beam lithography, focused ion beam lithography or scanning probe nanolithography. The novel approach presented in this letter is the exploitation of X-ray lithography in the Elettra synchrotron to fabricate arrays of nanocontacts spaced a few nanometers, devoted to the design of a new class of nanodevices based on nanoparticles and/or single molecules, including single electron transistors and highly sensitive biosensors. The method to fabricate such devices is illustrated and discussed. Experimental details of the fabrication process are given and preliminary results are presented through SEM and AFM images. It is worth noting that this paper presents a viable method to produce nanocontacts by using the X-ray lithography by synchrotron radiation source, that has not yet been reported together with experimental, though preliminary, data.
The usefulness of zinc oxide (ZnO) nanoparticles has led to their wide distribution in consumer products, despite only a limited understanding of how this nanomaterial behaves within biological ...systems. From a nanotoxicological viewpoint the interaction(s) of ZnO nanoparticles with cells of the immune system is of specific interest, as these nanostructures are readily phagocytosed. In this study, rapid scanning X-ray fluorescence microscopy was used to assay the number ZnO nanoparticles associated with ∼1000 individual THP-1 monocyte-derived human macrophages. These data showed that nanoparticle-treated cells endured a 400% elevation in total Zn levels, 13-fold greater than the increase observed when incubated in the presence of an equitoxic concentration of ZnCl2. Even after excluding the contribution of internalized nanoparticles, Zn levels in nanoparticle treated cells were raised ∼200% above basal levels. As dissolution of ZnO nanoparticles is critical to their cytotoxic response, we utilized a strategy combining ion beam milling, X-ray fluorescence and scanning electron microscopy to directly probe the distribution and composition of ZnO nanoparticles throughout the cellular interior. This study demonstrated that correlative photon and ion beam imaging techniques can provide both high-resolution and statistically powerful information on the biology of metal oxide nanoparticles at the single-cell level. Our approach promises ready application to broader studies of phenomena at the interface of nanotechnology and biology.
•XRF analyses investigated Gd retention 1 month after linear GBCAs administration in a renal disease model.•Macro XRF was useful to detect Gd in the incisors of the nephrectomised GBCAs treated ...animals.•Sub-micro XRF and LA-ICP analyses specifically revealed Gd in the periodontal ligament.
Gadolinium deposition in tissue is linked to nephrogenic systemic fibrosis (NSF): a rare disorder occurring in patients with severe chronic kidney disease and associated with administration of Gd-based contrast agents (GBCAs) for Magnetic Resonance Imaging (MRI). It is suggested that the GBCAs prolonged permanence in blood in these patients may result in a Gd precipitation in peripheral or central organs, where it initiates a fibrotic process. In this study we investigated new sites of retention/precipitation of Gd in a mouse model of renal disease (5/6 nephrectomy) receiving two doses (closely after each other) of a linear GBCA. Two commercial GBCAs (Omniscan® and Magnevist®) were administered at doses slightly higher than those used in clinical practice (0.7 mmol/kg body weight, each). The animals were sacrificed one month after the last administration and the explanted organs (kidney, liver, femur, dorsal skin, teeth) were analysed by X-ray fluorescence (XRF) at two synchrotron facilities. The XRF analysis with a millimetre-sized beam at the SYRMEP beamline (Elettra, Italy) produced no detectable levels of Gd in the examined tissues, with the notable exception of the incisors of the nephrectomised mice. The XRF analyses at sub-micron resolution performed at ID21 (ESRF, France) allowed to clearly localize Gd in the periodontal ligaments of teeth both from Omniscan® and Magnevist® treated nephrectomised mice. The latter results were further confirmed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The study prompts that prolonged permanence of GBCAs in blood may result in Gd retention in this particular muscular tissue, opening possibilities for diagnostic applications at this level when investigating Gd-related toxicities.
The possibility of fast X‐ray fluorescence (XRF) imaging using on‐the‐fly acquisition is very attractive due to its high acquisition speed. The underlying assumption is that there must be a ...meaningful flux of XRF emitted photons collected by the detectors. On‐the‐fly XRF has already been demonstrated at mid‐to‐high X‐ray energies, both for laboratory and synchrotron‐based instruments.
In this manuscript, we report on the capability of DANTE digital pulse processor (DPP) in the soft X‐ray regime. DANTE is a novel compact and low‐power DPP with high energy resolution and high count rate. This work presents preliminary measurements performed at the TwinMic beamline at Elettra synchrotron (Trieste, Italy) addressing the feasibility of on‐the‐fly low energy XRF imaging.
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