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Self-Propelled Nanomotors
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Nanoparticle tracking analysis (NTA) provides a tracking method for measuring the diffusion and concentration of particles from about 30 to 1000 nm, with the lower detection limit being dependent on the dielectric properties of the nanoparticles. The technique consists of a laser scattering setup similar to DLS but with a custom-made microfluidic device and a CCD camera, which permits the visualization of nanoparticles by recording their scattered light (see Figure 13.9a). A laser beam passes through the sample chamber, the particles in suspension in the path of the beam scatter light and is visualized on a x20 magnification objective attached to a CCD camera.
Organic and Inorganic Nanoparticles from Agricultural Waste
Published in Sefiu Adekunle Bello, Hybrid Polymeric Nanocomposites from Agricultural Waste, 2023
Particle size distribution of nanoparticles can be determined by particle size analyser (PSA). Dynamic light scattering (DLS) for measurement of average particle size of nanoparticles. Nanoparticle tracking analysis (NTA) allows direct tracking of Brownian motion of individual nanoparticles thus providing means of measuring particle sizes of individual entities in solution. Tunable resistive pulse sensing (TRPS) enables the simultaneous measurement of size, concentration, and surface charge for a wide variety of nanoparticles.
Advances of engineered extracellular vesicles-based therapeutics strategy
Published in Science and Technology of Advanced Materials, 2022
Hiroaki Komuro, Shakhlo Aminova, Katherine Lauro, Masako Harada
The dosing and quantification of engineered EVs vary widely among studies. Gupta et al. investigated the effective dosage in the target disease and observed inconsistency [202]. In preclinical and clinical studies, it is necessary to quantify the amount of engineered EVs to be administered. Currently, there are various methods, such as protein concentration, particle number, and drug concentration equivalent (Figure 2E). These methods have their own advantages and disadvantages. For example, the amount of protein can be easily assessed but may vary depending on the EV source and EV isolation method [203]. The particle number is counted using special equipment such as nanoparticle tracking analysis (NTA). The equipment used may also affect the concentration of the particles and the setting of the measurement conditions, as particle measurement accuracy depends on the sample and the preparation method. There needs to be standardization in the description of these doses.
Morphological and photoluminescence study of NaSrB5O9: Tb3+ nanocrystalline phosphor
Published in Journal of Asian Ceramic Societies, 2018
Vaishali Raikwar, Vinod Bhatkar, Shreeniwas Omanwar
NaSr1-xB5O9:xTb3+ phosphors doped with various molar concentrations of Tb3+ (x = 0.005, 0.01, 0.02, 0.03, 0.05) were prepared by a modified combustion technique. The synthesis is based on an exothermic reaction between the fuel and oxidizer. Urea was used as the fuel and metal nitrates as the oxidizer. For complete combustion the oxidizer-to-fuel ratio should be one-to-one. All the precursors viz. sodium nitrate, strontium nitrate, urea and boric acid (as the boron source) were procured as analytical reagents (AR), weighed in stoichiometric proportions and dissolved in a minimum amount of distilled water. Terbium nitrate was prepared by adding dilute HNO3 to terbium oxide followed by continuous stirring. The precursor paste was mixed well to assure homogenization of the mass. A quartz container containing this paste was placed in a furnace maintained at around 550°C. After about 2–3 min a reaction with bright yellow flames started. The reaction continued for only a few seconds. As soon as the reaction was over, the quartz container was removed from the furnace and allowed to cool. The prepared phosphor was crushed to a fine powder using a mortar and pestle. The same process flow was followed for the different concentrations of Tb3+. The samples were subjected to X-ray diffraction (XRD) analysis using a Rigaku Miniflex diffractometer with Cu Kα radiation (λ = 1.54059 A°) operating at 40 kV and 30 mA. The XRD data was collected in the 2θ range from 10° to 70° at room temperature. Fourier transform infrared (FTIR) spectroscopy was conducted on a Shimatzu IR Prestige −21 analyser. The measurements concerning particle size were done with a nanoparticle tracking analysis (NTA) system that uses a laser to track the Brownian motion of particles in samples. The measurements of photoluminescence emission (PL) over the range of 450 to 650 nm and photoluminescence excitation spectra (PLE) over a 200 to 400 nm excitation range were conducted with a Hitachi F 7000 fluorescence spectrophotometer at room temperature. The spectral resolution of both the excitation and emission spectra widths of the monochromatic slits (1 nm) as well as of measurement conditions such as the photomultiplier tube detector’s sensitivity and scanning speed were kept constant for all the samples. Electron diffraction X-ray spectroscopy (EDX) for elemental analysis and field emission scanning electron microscopy (FESEM) for detecting the morphology of the samples was conducted on a Hitachi S-4800 FESEM with a maximum resolution of 1.0 nm and a variable acceleration voltage of 0.5–30 kV. All the samples were coated with a thin layer of gold in the FESEM analysis to avoid charging. The color chromaticity coordinates were obtained following the standards of the Commission International de I’Eclairage (CIE) using Radiant Imaging Color Calculator 2.0 software.