had developed cross-linked nanoparticles of polyethylene amine and triphosphate (PEI-TPP) for gene delivery. The average particle size of the hydrolyzed cotton nanoparticles determined by DLS was found to be less than 100 nm ( Meyabadi et al., 2014). Characterization of the prepared nanoparticle was performed using viscometer, field emission SEM, DLS, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). prepared cellulose nanoparticles from cotton waste via an enzymatic hydrolysis technique. The results obtained by DLS are usually verified by another size characterization technique such as TEM ( Bhattacharjee, 2016). For this particle size measurement, a disposable polystyrene cuvette filled with samples may be placed in Zetasizer Nano-ZS (Malvern Panalytical Ltd.) or equivalent instrument. In the equation, D is diffusion coefficient, k is Boltzmann’s constant, T is temperature, η is solvent viscosity, and Rh is the rheodynamic radius of particle solution ( Hoo et al., 2008). If the suspension is in aggregated form, then the diameter of particles measured by DLS is much larger than the TEM size analysis. If the suspension is in an unaggregated form, then size will be not that much difference between size analysis data of DLS and TEM. By comparing DLS and transmission electron microscopy (TEM) image data, the aggregation state of nanoparticles can be easily determined. Globule size of microemulsions may also be measured by DLS technique ( Raval et al., 2018a). DLS is the ultimate tool to determine and measure the agglomeration state of nanoparticles. The smaller the particle, the faster it will diffuse than a larger one and the DLS instrument will generate a correlation function that is mathematically linked with particle size and its time-dependent light scattering capacity.ĭLS has been used to measure the particle size of dispersing colloidal samples, to study the stability of formulations, and to detect the presence of aggregation or agglomeration. Brownian motion of particles correlates with their hydrodynamic diameter. DLS measures the hydrodynamic size of particles, by the mechanism of light scattering from a laser that passes through colloidal solution and analyzes modulation of the intensity of scattered light as a function of time ( Lim et al., 2013).

Tekade, in Basic Fundamentals of Drug Delivery, 2019 10.3.1.1 Dynamic Light Scatteringĭynamic light scattering (DLS), which is also referred to as photon correlation spectroscopy (PCS) or quasi-elastic light scattering, is used to determine the nanoparticle size in the colloidal suspension polymeric solution.

Dynamic light scattering nanoparticle