Scanning electrochemical microscopy (SECM) is an electroanalytical scanning probe technique capable of imaging substrate topography and local reactivity with high resolution. Since its inception in ...1989, it has expanded into a wide variety of research areas including biology, corrosion, energy, kinetics, instrumental development, and surface modification. In the past 25 years, over 1800 peer-reviewed publications have focused on SECM, including several topical reviews. However, these reviews often omit key details, forcing readers to search the literature. In this review, we provide a comprehensive summary of the experimental parameters (e.g., solvents, probes, and mediators) used in all SECM publications since 1989, irrespective of the application. It can be used to rapidly assess experimental possibilities and make an informed decision about experimental design. In other words, it is a practical guide to SECM.
•CoFe2O4 nanoparticles were prepared by co-precipitation using 4 precipitating agents.•The intermediate products were calcined at 600 °C for 4 h.•X-ray peak profile analysis (XPPA) were used to ...estimate the physical parameters.•D-S method, W-H plot, H-W plot & SSP technique results were highly intercorrelated.•XRD, SEM, TEM, DLS & ζ-potential results indicate KOH as the most suitable alkali.
Cobalt ferrite (CoFe2O4) nanoparticles have been developed by co-precipitation technique using four distinct precipitating agents, e.g., mixture of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3), sodium hydroxide (NaOH), ammonium hydroxide (NH4OH), potassium hydroxide (KOH). The prepared systems had been investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Nanoparticle analyzer and Transmission electron microscopy (TEM). X-ray peak profile analysis (XPPA) had been used to estimate the physical parameters such as crystallite size and lattice strain by Debye-Scherrer (D-S) method, Williamson-Hall (W-H) plot, Halder-Wagner (H-W) technique and Size-Strain plot (SSP) technique. Different precipitating agents influence strongly the structure, size distribution, morphology and stability of the nanoparticles and on the basis of these parameters an optimum sample had been selected. The crystallite size calculated from XRD and particle size calculated from SEM shows a narrow size distribution with averages between 26.6–50.4 nm and 54–98 nm respectively, for all the samples. The particle size obtained from TEM shows high compatibility with XRD results with averages between 20 and 50 nm. The average lattice strain, dislocation density, lattice constant, cell volume, zeta potential was between 0.00094 and 0.0015, (4.34–14.13) × 1014 (lines/m2), 8.36870–8.38558 Å, 586.10–589.65 Å3, −87.8–27.7 mV respectively. The results estimated from the D-S method, W-H plot, H-W plot, SSP technique, SEM, Nanoparticle Analyzer and TEM regarding the structural and morphological parameters of the CoFe2O4 nanoparticles had been highly intercorrelated. Among the XPPA methods, SSP method is the most compatible one since the data points more accurately fits in this method with average correlation coefficient value (R2) of 0.99 that has been reinforced from TEM results as well. The synthesized CoFe2O4 nanoparticles can be applicable as liquid black coloring agent on ceramic surface after mixing with suitable solvent.
Several imaging methodologies have been used in biofilm studies, contributing to deepening the knowledge on their structure. This review illustrates the most widely used microscopy techniques in ...biofilm investigations, focusing on traditional and innovative scanning electron microscopy techniques such as scanning electron microscopy (SEM), variable pressure SEM (VP-SEM), environmental SEM (ESEM), and the more recent ambiental SEM (ASEM), ending with the cutting edge Cryo-SEM and focused ion beam SEM (FIB SEM), highlighting the pros and cons of several methods with particular emphasis on conventional SEM and VP-SEM. As each technique has its own advantages and disadvantages, the choice of the most appropriate method must be done carefully, based on the specific aim of the study. The evaluation of the drug effects on biofilm requires imaging methods that show the most detailed ultrastructural features of the biofilm. In this kind of research, the use of scanning electron microscopy with customized protocols such as osmium tetroxide (OsO
), ruthenium red (RR), tannic acid (TA) staining, and ionic liquid (IL) treatment is unrivalled for its image quality, magnification, resolution, minimal sample loss, and actual sample structure preservation. The combined use of innovative SEM protocols and 3-D image analysis software will allow for quantitative data from SEM images to be extracted; in this way, data from images of samples that have undergone different antibiofilm treatments can be compared.
Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, ...advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications.
Summary
Volume and surface area of chloroplasts and surface area of plasmodesmata pit fields are presented for two C4 species, maize and sugarcane, with respect to cell surface area and cell volume.
...Serial block face scanning electron microscopy (SBF‐SEM) and confocal laser scanning microscopy with the Airyscan system (LSM) were used. Chloroplast size estimates were much faster and easier using LSM than with SBF‐SEM; however, the results were more variable than SBF‐SEM.
Mesophyll cells were lobed where chloroplasts were located, facilitating cell‐to‐cell connections while allowing for greater intercellular airspace exposure. Bundle sheath cells were cylindrical with chloroplasts arranged centrifugally. Chloroplasts occupied c. 30–50% of mesophyll cell volume, and 60–70% of bundle sheath cell volume. Roughly 2–3% of each cell surface area was covered by plasmodesmata pit fields for both bundle sheath and mesophyll cells.
This work will aid future research to develop SBF‐SEM methodologies with the aim to better understand the effect of cell structure on C4 photosynthesis.
SUMMARY
Leaf plastids harbor a plethora of biochemical reactions including photosynthesis, one of the most important metabolic pathways on Earth. Scientists are eager to unveil the physiological ...processes within the organelle but also their interconnection with the rest of the plant cell. An increasingly important feature of this venture is to use experimental data in the design of metabolic models. A remaining obstacle has been the limited in situ volume information of plastids and other cell organelles. To fill this gap for chloroplasts, we established three microscopy protocols delivering in situ volumes based on: (i) chlorophyll fluorescence emerging from the thylakoid membrane, (ii) a CFP marker embedded in the envelope, and (iii) calculations from serial block‐face scanning electron microscopy (SBFSEM). The obtained data were corroborated by comparing wild‐type data with two mutant lines affected in the plastid division machinery known to produce small and large mesophyll chloroplasts, respectively. Furthermore, we also determined the volume of the much smaller guard cell plastids. Interestingly, their volume is not governed by the same components of the division machinery which defines mesophyll plastid size. Based on our three approaches, the average volume of a mature Col‐0 wild‐type mesophyll chloroplasts is 93 μm3. Wild‐type guard cell plastids are approximately 18 μm3. Lastly, our comparative analysis shows that the chlorophyll fluorescence analysis can accurately determine chloroplast volumes, providing an important tool to research groups without access to transgenic marker lines expressing genetically encoded fluorescence proteins or costly SBFSEM equipment.
Significance Statement
This work describes and compares three different strategies to obtain accurate volumes of leaf plastids from Arabidopsis, the most widely used model plant. We hope our contribution will support quantitative metabolic flux modeling and spark other projects aimed at a more metric‐driven plant cell biology.
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