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Light Scattering Techniques for Characterization of NANPs and Their Formulations
Published in Peixuan Guo, Kirill A. Afonin, RNA Nanotechnology and Therapeutics, 2022
Lewis A. Rolband, Joanna K. Krueger
Dynamic light scattering (DLS) is an efficient method for initial characterization of particle sizes within a wide range. DLS is a technique that measures the change in the intensity of scattered light at a fixed angle, over microsecond intervals, due to the random Brownian motion of particles in solution as they diffuse [3–6]. As such, the translational diffusion coefficient, Dt, is directly calculated from the time-correlated scattering intensity changes and then related to several other important parameters. The two most relevant parameters to RNA nanotechnology derived from the Dt are the hydrodynamic radius, Rh, and the diffusion interaction parameter, kD. The Rh is significant as an estimate of nanoparticle size in solution, as it represents the radius of a sphere that would diffuse at the same rate as the particle under investigation [7, 8]. Additionally, Rh can be used to gain insights into complex formation or conformational changes [8]. To assess colloidal stability, kD can be calculated from the scattering data and is directly related to the second virial coefficient, A2 [6]. A positive value of kD implies repulsive interactions between particles, while a negative value implies attractive interactions [6, 9].
Characterization Techniques for Bio-Nanocomposites
Published in Shrikaant Kulkarni, Neha Kanwar Rawat, A. K. Haghi, Green Chemistry and Green Engineering, 2020
DLS is based on the analysis of the variations in the intensity of the scattered light on illumination of particles. The size of a particle and its mobility because of Brownian motion is deduced by the Stokes-Einstein equation. A monochromatic radiation with frequency, 0, is incident then the colloid gives a spectrum having a Lorentzian shape, with the peak width which is determined from the product of diffusion coefficient of the particles, D, and Q2: I(É)∞DQ2É−É02+DQ22
Nanocarriers as a Strategy for Oral Bioavailability Improvement of Poorly Water-SolubleDrugs
Published in Ana Rute Neves, Salette Reis, Nanoparticles in Life Sciences and Biomedicine, 2018
Luise L. Chaves, Alexandre C. Vieira, Domingos Ferreira, Bruno Sarmento, Salette Reis, Sofia A. Costa Lima
The dynamic light scattering (DLS) is one of the most popular techniques used to estimate the size distribution of small particles in solution or suspension. The data obtained provide information about a population of nanocarriers in each sample solution, and not information about each particle. The main strengths of DLS are that the experiment duration is short, the technique is noninvasive, diluted samples can be measure in a wide range of concentrations, and even small amounts of higher-molecular-weight species can be detected. However, the high accuracy of the technique can, sometimes, lead to a wrong interpretation of the data as the presence of even a small percentage of aggregates may interfere in the scattering intensity, increasing the size of measured particle. In the case of nanocarriers with poorly soluble drugs, proper dilution sometimes is not enough to solubilize unentrapped drugs in suspension, and these particles are also measured, giving false results of bigger nanocarriers.
Size controlled, time-efficient biosynthesis of silver nanoparticles from Pleurotus florida using ultra-violet, visible range, and microwave radiations
Published in Inorganic and Nano-Metal Chemistry, 2020
Gagandeep Kaur, Anu Kalia, Harpreet S. Sodhi
DLS is a fast and easy technique for particle characterization, especially for measuring the hydrodynamic size distribution of colloidal suspensions.[41] The DLS data (Figure 4) showed similar trend in terms of size and uniformity as was shown by transmission electron micrographs. However, hydrodynamic radii of nanoparticles in DLS appeared much larger than those found in TEM results, possibly due to polydispersity phenomenon. Sample polydispersity can distort the results as the bigger particles presented in the sample can screen smaller ones.[42] Kumar et al.[25] reported similar results of hydrodynamic radii of AgNPs synthesized using Capuli cherry extracts. The light and UV rays irradiated sols exhibited zeta potential values of –11.0 and –15.5 mV, respectively. However, the microwave irradiated AgNP sol had zeta potential value of –20.1 mV. Similar zeta potential values have also been reported for the mycosynthesized AgNPs using Trichoderma longibrachiatum[43] and Ganoderma sessiliforme.[44]
Investigations on the thermal and electrical conductivity of polyethylene glycol-based CuO and ZnO nanofluids
Published in Indian Chemical Engineer, 2020
Swaminathan Ponmani, Pawan Gupta, Prashant Jadhawar, R. Nagarajan, Jitendra Sangwai
DLS measures particle size distribution in a range of nanofluids. The Brownian diffusivity of particles is measured using DLS and is related to their size. The particle size is measured by illuminating the particles with a laser and analysing the intensity fluctuations in the scattered light. The DLS measurements were carried out using 90 PlusTM Nanoparticle Size Analyzer by Brookhaven Instruments. It is capable of measuring particle size distributions in the range of 1 nm to 6 µm with a precision of ± 1%. Measurements were made at 90° scattering angle and at 25°C. DLS works on the principle that when the sample is illuminated by a laser beam, the fluctuations of the scattered light are detected at a known scattering angle by a detector.
Green synthesis of silver nanoparticles by seed of Phoenix sylvestris L. and their role in the management of cosmetics embarrassment
Published in Green Chemistry Letters and Reviews, 2018
Afifa Qidwai, Rajesh Kumar, Anupam Dikshit
Dynamic light scattering (DLS) is a technique that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. A laser diffraction method with a multiple scattering technique has been used to ascertain the size range of nanoparticle and distribution of the particle in a sample (Mie-scattering theory). In order to find out the particles size distribution of the Ag NPs, the powder was dispersed in ddw and ultrasonicated. Further experiments were carried out on a computer-based particle size analyzer (Nanotrac wave W3372) to find out the particle size distribution (Figure 1(B)).