The atomic force microscopy (AFM) is an important tool capable of characterization, measurement, and manipulation at the nanoscale with a vertical resolution of less than 0.1 nm. However, the ...conventional AFMs' scanning range is around 100 µm, which limits their capability for processing cross‐scale samples. In this study, it proposes a novel approach to overcome this limitation with an ultra‐large scale stitchless AFM (ULSS‐AFM) that allows for the high‐throughput characterization of an area of up to 1 × 1 mm2 through a synergistic integration with a compliant nano‐manipulator (CNM). Specifically, the compact CNM provides planar motion with nanoscale precision and millimeter range for the sample, while the probe of the ULSS‐AFM interacts with the sample. Experimental results show that the proposed ULSS‐AFM performs effectively in different scanning ranges under various scanning modes, resolutions, and frequencies. Compared with the conventional AFMs, the approach enables high‐throughput characterization of ultra‐large scale samples without stitching or bow errors, expanding the scanning area of conventional AFMs by two orders of magnitude. This advancement opens up important avenues for cross‐scale scientific research and industrial applications in nano‐ and microscale.
An ultra‐large scale stitchless atomic force microscopy that enables the characterization of a maximum area of 1 × 1 mm2 through the innovative integration of a compliant nano‐manipulator. This approach enables the characterization of ultra‐large scale samples with zero stitching error and high throughput, expanding the scanning area of conventional AFMs by two orders of magnitude.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Treatment of graphene growth substrates with H2 has long been known to impact the quality of deposited graphene. However, the parameters for hydrogen treatment that are considered the optimum – very ...long anneals under low hydrogen concentrations – are often undesirable for practical reasons. In this paper we optimize anneal parameters for fast anneals of <1 h, via investigation of both substrate surface modification and graphene growth quality using a number of traditional and novel experimental techniques. Our results indicate a dual effect of H2 annealing on the surface morphology of the copper substrate, and consequent graphene growth quality, whereby H2 passivates and smoothens the Cu surface, causing it to become morphologically more favorable for graphene growth, but may in large quantities make the surface less chemically favorable, limiting the quality of grown graphene. Moreover, we use a novel method based on Atomic Force Microscopy (AFM) for higher spatial resolution analysis of the homogeneity of graphene using maps of the Hamaker coefficient.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Graphene nanoribbons (GNRs) have gained significant attention in nanoelectronics due to their potential for precise tuning of electronic properties through variations in edge structure and ribbon ...width. However, the synthesis of GNRs with highly sought‐after zigzag edges (ZGNRs), critical for spintronics and quantum information technologies, remains challenging. In this study, a design motif for synthesizing a novel class of GNRs termed edge‐extended ZGNRs is presented. This motif enables the controlled incorporation of edge extensions along the zigzag edges at regular intervals. The synthesis of a specific GNR instance—a 3‐zigzag‐rows‐wide ZGNR—with bisanthene units fused to the zigzag edges on alternating sides of the ribbon axis is successfully demonstrated. The resulting edge‐extended 3‐ZGNR is comprehensively characterized for its chemical structure and electronic properties using scanning probe techniques, complemented by density functional theory calculations. The design motif showcased here opens up new possibilities for synthesizing a diverse range of edge‐extended ZGNRs, expanding the structural landscape of GNRs and facilitating the exploration of their structure‐dependent electronic properties.
In this study, a new design motif is introduced to synthesize edge‐extended zigzag graphene nanoribbons (ZGNRs). Using scanning probe techniques and density functional theory, the chemical structure and electronic characteristics of a 3‐zigzag‐row ZGNR instance are confirmed. This approach expands the range of possible ZGNRs, contributing to further understanding of structure‐dependent electronic properties in GNRs.
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Phosphatidylserine (PS) in the plasma membrane plays an important role in cell signaling and apoptosis. Cell degeneration is also linked to numerous amyloid diseases, pathologies that are associated ...with aggregation of misfolded proteins. In this work, we examine the effect of both saturated PS (DMPS) and unsaturated PS (DOPS and POPS) on the aggregation properties of insulin, as well as the structure and toxicity of insulin aggregates formed in the presence of these phospholipids. We found that the degree of unsaturation of fatty acids in PS alters the rate of insulin aggregation. We also found that toxicity of insulin–DMPS aggregates is significantly lower than the toxicity of DOPS– and POPS–insulin fibrils, whereas all these lipid‐containing aggregates exert lower cell toxicity than insulin fibrils grown in a lipid‐free environment.
Using comprehensive biophysical and biochemical approaches, we examined the effects of saturated and unsaturated fatty acids in plasma membrane phosphatidylserine on insulin aggregation, as well as on the structure and toxicity of amyloid aggregates. Our findings suggest that PS plays an important role in the stability and toxicity of amyloidogenic proteins on or in lipid bilayers.
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Carbon nanotubes (CNTs) are cylindrical nanostructures fabricated from carbon atoms that seem like seamless cylinders composed of rolled sheets of graphite. Owing to the unique properties of ...single-walled carbon nanotubes (SWCNTs), they are a promising candidate in various fields such as chemical sensing, hydrogen storage, catalyst support, electronics, nanobalances, and nanotubes. Because of their small size, large surface area, high sensitivity, and reversible behavior at room temperature, CNTs are ideal for measuring gas. They also show improved electron transfer when used as electrodes in electrochemical reactions and serve as solid media for protein immobilization on biosensors. SWCNTs can be metallic or semi-conductive, counting on their structural properties. In this study, an atomic force microscope (AFM) was used as a powerful tool to manipulate and disaggregate SWCNTs. By precisely controlling the AFM probe, it was possible to manipulate individual SWCNTs and separate them from the bundle structures. Next, the electrical transport of disaggregated SWCNTs was studied using the conductive atomic force microscope (cAFM) technique. Thus, current-voltage measurements on the unbundled branches of SWCNTs were carried out. Interestingly, these current-voltage measurements have allowed us to unravel the complex electrical characteristics of the nanotube bundle, which is a very crucial issue for gating effects as well as the resistance of the interconnects within carbon nanotube network devices.
In this work, the influence of the rigid substrate on the determination of the sample Young's modulus, the so‐called bottom‐effect artifact, is demonstrated by an atomic force microscopy ...force‐spectroscopy experiment. The nanomechanical properties of a one‐component supported lipid membrane (SLM) exhibiting areas of two different thicknesses are studied: While a standard contact mechanics model (Sneddon) provides two different elastic moduli for these two morphologies, it is shown that Garcia's bottom‐effect artifact correction yields a unique value, as expected for an intrinsic material property. Remarkably, it is demonstrated that the ratio between the contact radius (and not only the indentation) and the sample thickness is the key parameter addressing the relevance of the bottom‐effect artifact. The experimental results are validated by finite element method simulations providing a solid support to Garcia's theory. The amphiphilic nature of the investigated material is representative of several kinds of lipids, suggesting that the results have far reaching implications for determining the correct Young's modulus of SLMs. The generality of Garcia's bottom‐effect artifact correction allows its application to every kind of supported soft film.
An atomic force microscopy force‐spectroscopy experiment is designed to investigate the so‐called bottom‐effect artifact affecting the nanomechanical properties of a supported lipid bilayer. While standard contact mechanics does not compensate this artifact, a full support is provided to Garcia's theory as the proper approach to measure the correct Young's modulus of soft samples supported on rigid substrates.
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•Typical bee-like structures with AFM change in size after short- and long-term laboratory ageing.•The fibril network in ESEM is getting denser and coarser with ageing.•CLSM fluorescent centres ...remain unaffected in terms of size by ageing or disappear upon oxidation.•CLSM in reflectance mode is the most promising future microscopy for ageing in bitumen.•A common preparation procedure for bituminous microscopic samples is proposed.
Undoubtedly bitumen’s viscoelastic performance has received much attention in the literature. Especially, the oxidative ageing phenomenon of bitumen has been studied by several scholars from different physicochemical and mechanical perspectives due to its direct impact on asphalt performance. The microstructural patterns observed with ageing utilising different microscopic techniques have not remained unexplored, and an increasing interest has been expressed to understand the bitumen’s architecture by coupling it with different theories. This review aims to provide a useful guide for the road engineer by collecting all the existing microstructural trends that have been reported upon ageing by utilising some of the most promising microscopic techniques. The study demonstrates the changes being observed for the size of the so-called bee structures via Atomic Force Microscopy (AFM). The apparent fibril microstructure captured with Environmental Scanning Electron Microscopy (ESEM) consistently reported in the literature to become denser and coarser with ageing. The existing findings of Confocal Laser Scanning Microscopy (CLSM) revealed the conflicting observations that exist for the fluorescent centres of bitumen upon oxidation, concerning their size and number. Finally, this paper provides a comparative analysis of the three techniques for bitumen applications and recommends a systematic sample preparation protocol to move towards more consistent observations between the different research groups.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Fast quantitative mapping of mechanical properties with nanoscale spatial resolution represents one of the major goals of force microscopy. This goal becomes more challenging when the ...characterization needs to be accomplished with subnanometer resolution in a native environment that involves liquid solutions. Here we demonstrate that bimodal atomic force microscopy enables the accurate measurement of the elastic modulus of surfaces in liquid with a spatial resolution of 3 Å. The Young’s modulus can be determined with a relative error below 5% over a 5 orders of magnitude range (1 MPa to 100 GPa). This range includes a large variety of materials from proteins to metal–organic frameworks. Numerical simulations validate the accuracy of the method. About 30 s is needed for a Young’s modulus map with subnanometer spatial resolution.
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Abrupt aggregation of misfolded proteins is a hallmark of the large group of amyloid pathologies that include diabetes type 2, Alzheimer and Parkinson's diseases. Protein aggregation yields oligomers ...and fibrils, β‐sheet‐rich structures that exert cell toxicity. Microscopic examination of amyloid deposits reveals the presence of lipids membranes, which suggests that lipids can be involved in the process of pathogenic protein assembly. In this study, we show that lipids can uniquely alter the aggregation rates of lysozyme, a protein that is associated with systemic amyloidosis. Specifically, cardiolipin (CL), ceramide (CER), and sphingomyelin (SM) accelerate, phosphatidylcholine (PC) strongly inhibits, whereas phosphatidylserine (PS) has no effect on the rate of protein aggregation. Furthermore, lipids uniquely alter the secondary structure of lysozyme aggregates. Furthermore, we found that lysozyme aggregates grown in the presence of CL, CER, SM, PS, and CL:PC mixtures exert significantly lower production of reactive oxygen species and mitochondrial dysfunction compared to lysozyme:PC aggregates and lysozyme fibrils grown in the lipid‐free environment. These findings suggest that a change in the lipid composition of cell membranes, which is taken place upon neurodegeneration, may trigger the formation of toxic protein species that otherwise would not be formed.
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•Microplastics in surface and groundwater.•Toxicological heavy metal interaction between microplastics and water.•OSPRC framework for transmission route evaluation.•Microplastics is a ...possible vector of environmental pollution.
Study of hazardous microplastics in the natural water resources is minimal compared to the sea salt, seafood and even packaged water. We presented results of the first baseline research of microplastics in groundwater and surface water from the coastal south India (Tamil Nadu state) and evaluated the heavy metal adsorption capacities of different polymers. The microplastics (up to 19.9 particles/L) were of relatively larger size in surface water (0.34–4.30 mm) compared to the groundwater (0.12–2.50 mm). Polyamide (nylon), polyester, polypropylene, polyethylene, polyvinyl chloride and cellulose were the common polymers and all of them showed different capacities of heavy metal adsorption. In two different experimental sites, the polypropylene showed higher capacity of adsorption compared to other polymers in the following orders: (i) cadmium > manganese > lead > arsenic and (ii) manganese > zinc > arsenic > lead > copper. The polyamide, however, exhibited better adsorption only for manganese. Similar to other recent findings, our results associate microplastics as a major vector to transport heavy metals in the water system. Formulation of strategies to reduce the environmental risks of particulate plastics as a potent vector for transportation of the toxic trace elements and subsequent, impact on human health through the OSPRC framework (Origins, Sources, Pathways, Receptors and Consequence) in the study area would require future research.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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