For either reason, the MNP’s size is one of the determining factors. The technique of dynamic light scattering (DLS) has been
widely employed for sizing MNPs in liquid phase [22, 23]. However, the precision of the determined particle size is not completely understood due to a number of unevaluated effects, such as concentration of particle suspension, scattering angle, and shape anisotropy of nanoparticles . In this review, the underlying working principle of DLS is first provided to familiarize the readers with the mathematical analysis involved for correct #this website randurls[1|1|,|CHEM1|]# interpretation of DLS data. Later, the contribution from various factors, such as suspension concentration, particle shape, colloidal stability, and surface coating of MNPs, in dictating the sizing of MNPs by DLS is discussed in detail. It is the intention of this review to summarize some of the important considerations in using DLS as an analytical tool for the characterization of MNPs.
Overview of sizing techniques for MNPs There are numerous analytical techniques, such as DLS , transmission electron miscroscopy (TEM) , thermomagnetic measurement , dark-field microscopy [17, 18], atomic force microscopy (AFM) , and acoustic spectrometry measurement , that have been employed to measure the size/size distribution of MNPs (Table 1). TEM is one of the most powerful analytical tools available PF-2341066 which can give direct structural and size information of the MNP. Through the use of the short wavelengths achievable with highly accelerated electrons, it is capable to investigate the structure of a MNP down to the atomic level of detail, whereas by performing image analysis on
the TEM micrograph obtained, Olopatadine it is possible to give quantitative results on the size distribution of the MNP. This technique, however, suffered from the small sampling size involved. A typical MNP suspension composed of 1010 to 1015 particles/mL and the size analysis by measuring thousands or even tens of thousands of particles still give a relatively small sample pool to draw statistically conclusive remarks. Table 1 Common analytical techniques and the associated range scale involved for nanoparticle sizing Techniques Approximated working size range Dynamic light scattering 1 nm to approximately 5 μm Transmission electron microscopy 0.5 nm to approximately 1 μm Atomic force microscopy 1 nm to approximately 1 μm Dark-field microscopy 5 to 200 nm Thermomagnetic measurement 10 to approximately 50 nm Thermomagnetic measurement extracts the size distribution of an ensemble of superparamagnetic nanoparticles from zero-field cooling (ZFC) magnetic moment, m ZFC(T), data based on the Néel model .