{"id":71,"date":"2020-01-01T01:52:19","date_gmt":"2020-01-01T06:52:19","guid":{"rendered":"https:\/\/www.cd-bioparticles.com\/blog\/?p=71"},"modified":"2020-01-01T01:52:19","modified_gmt":"2020-01-01T06:52:19","slug":"techniques-for-nanoparticle-size-characterization","status":"publish","type":"post","link":"https:\/\/www.cd-bioparticles.com\/blog\/nanoparticles\/techniques-for-nanoparticle-size-characterization\/","title":{"rendered":"Techniques for Nanoparticle Size Characterization"},"content":{"rendered":"\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"\/blog\/wp-content\/uploads\/2020\/01\/Techniques-for-Nanoparticle-Size-Characterization-1-1-1024x768.png\" alt=\"\" class=\"wp-image-73\" srcset=\"\/blog\/wp-content\/uploads\/2020\/01\/Techniques-for-Nanoparticle-Size-Characterization-1-1-1024x768.png 1024w, \/blog\/wp-content\/uploads\/2020\/01\/Techniques-for-Nanoparticle-Size-Characterization-1-1-300x225.png 300w, \/blog\/wp-content\/uploads\/2020\/01\/Techniques-for-Nanoparticle-Size-Characterization-1-1-768x576.png 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n\n<p>Particle size is an important detection index for nano-pharmaceutical preparations. All nano-pharmaceutical preparations must be tested for particle size and particle size distribution, including nano-emulsion, nano-crystals, nano-particles, and nanoplex. There are many particle size measuring instruments, including nanometer laser particle size measuring instruments and microscopes (such as transmission electron microscope and scanning electron microscope) based on dynamic light scattering technology.<\/p>\n\n\n\n<p><strong>Electron microscope technology<\/strong><\/p>\n\n\n\n<p>Transmission electron microscope (TEM) and scanning\nelectron microscope (SEM) are versatile electronic microscopy instruments. They\nare intuitive methods for particle size observation and measurement, and have\nhigh reliability. The size and shape of the nanometer drug delivery system can\nbe observed with an electron microscope, the particle thickness can be\nestimated based on the contrast of the image, and statistics can be combined\nwith image analysis to give a particle size distribution. If the particles are\nembedded and sliced to make thin samples, the microstructure inside the\nparticles can also be analyzed.<\/p>\n\n\n\n<p>In the electron microscope measurement, it should be noted\nthat: 1)The measured particle size may be the size of the aggregates, so when\npreparing the <a href=\"https:\/\/www.cd-bioparticles.com\/product\/nanoparticles-list-4.html\">nanoparticle<\/a> SEM sample,\nit should be fully dispersed; 2) The measurement result is not statistical\nbecause the amount of the electron microscope sample is very small. As a\nresult, the particles in the observation range are not representative; 3) The\nresult observed by electron microscope is particle size rather than grain size.<\/p>\n\n\n\n<p><strong>Dynamic laser scattering<\/strong><\/p>\n\n\n\n<p>Dynamic laser scattering (DLS), also known as photon\ncorrelation spectroscopy (PCS), is the most widely used method for analyzing\nparticle size of nanoparticles. This method obtains particle size information\nby measuring the diffusion coefficient of nanoparticles in a liquid. When\nnanoparticles are dispersed in a solvent, the particles diffuse in the solvent\ndue to the Brownian motion of the nanoparticles. The velocity of the Brown\nmoving particles is related to the particle size, which is consistent with the\nStokes-Einstein equation: d (H) = kT \/ 3 \u03c0\u03b7D. In the formula, d (H) is the\nparticle size; k is the Boltzmann constant; T is the thermodynamic temperature;\n\u03b7 is the viscosity; D is the diffusion coefficient.<\/p>\n\n\n\n<p>According to the viscosity \u03b7 of the solvent (dispersion\nmedium) and the dispersion temperature T, the particle diameter d can be\nobtained by measuring the diffusion coefficient D of the nanoparticles in the\ndispersion. The laser diffraction particle size analyzer is more accurate for\nsamples with a particle size of more than 5 \u03bcm; the dynamic light scattering\nparticle size analyzer is accurate for nano and sub-micron particle samples\nwith a particle size of less than 5 \u03bcm. In this method, it should be noted that\nthe best particles are spherical and monodisperse. In fact, the measured\nparticles are mostly irregular and polydisperse. The particle shape and\nparticle size distribution characteristics have a greater impact on the\nparticle size analysis results, and the more irregular the particle shape and\nthe wider the particle size distribution, the larger the error in the particle\nsize analysis results. Laser particle size analysis has the advantages of small\nsample consumption, high degree of automation, fastness, good repeatability,\nand online analysis. Its disadvantage is that it limits the concentration of\nthe sample and makes it difficult to analyze the particle size and particle\nsize distribution of the high concentration system. At present, there are\nadvanced instruments to relax the concentration range, but the sample with\nlower concentration is still more accurate than the sample with higher\nconcentration due to the small interparticle interference. When using a laser\nparticle size analyzer, you must have an understanding of the system particle\nsize range, otherwise the results may be biased.<\/p>\n\n\n\n<p><strong>Small-angle X-ray scattering method<\/strong><\/p>\n\n\n\n<p>Small-angle scattering refers to the phenomenon of coherent\nscattering near the reciprocal lattice origin (000) node in X-ray diffraction.\nSmall-angle X-ray scattering (SAXS) technology can study a variety of particles\nin the range of several nanometers to hundreds of nanometers. Analyzing the\nsmall-angle scattering pattern can obtain information on the long-period\nstructure of the substance, or the shape, scale, or mass information of the\nsubmicron particles (or pores). Small-angle scattering is an extremely powerful\ntechnique or tool for analyzing the spatial correlation of diffuse objects,\nsuch as polymer chains and macromolecules in solution.<\/p>\n\n\n\n<p><strong>Specific surface area method<\/strong><\/p>\n\n\n\n<p>According to the specific surface area S<sub>w<\/sub> of the unit mass\npowder, the diameter of the particles in the nanopowder can be calculated\n(assuming that the particles are spherical). The general measurement method of\nS<sub>w<\/sub> is\nthe BET multilayer gas adsorption method. Nitrogen is the adsorbent most commonly\nused by the specific surface area (BET) method, and the specific surface area\nranges from 0.1 to 1000m<sup>2<\/sup>\/g.\nThe advantage of this method is that the equipment is simple and the test speed\nis fast, but it is only the specific surface area information of the\nnano-powder. After conversion, the average particle size is obtained, but the\nparticle size distribution cannot be understood.<\/p>\n\n\n\n<p><strong>Atomic force microscopy<\/strong><\/p>\n\n\n\n<p>Atomic force microscopy (AFM) scans the surface of a sample\nby a tiny probe to convert the interaction between the probe and the surface of\nthe sample into a surface topography and characteristic image. Its advantage is\nthat it can provide a three-dimensional and high-resolution image of the\nsurface, and has a high horizontal and vertical resolution. In addition to\nmeasuring the particle size, it can also describe the sample shape. Its\ndisadvantages are small sample observation time and time consuming. Similar\ntechnologies to AFM include scanning transmission microscopy (STEM) and\nscanning transmission x-ray microscopy (STXM).<\/p>\n\n\n\n<p><strong>Selection of particle size measurement techniques<\/strong><\/p>\n\n\n\n<p>Nano drug delivery systems consist of a series of particles of varying sizes. Depending on the purpose of the measurement, the overall particle size distribution can be expressed by the number or volume diameter. The particle size distribution is determined not only by the average particle diameter, but also by the method of evaluating the average particle diameter. In addition, the particle distribution shape greatly affects the result of particle distribution. The influence of large particles on the calculation results in DLS measurement is very significant, and the scattered light of core-shell double-layer particles and single-layer particles with the same particle size distribution is different at different wavelengths. In practical applications, generally based on the actual particle size range, the detection method is reasonably selected, and two or more methods can be used to separately measure and verify each other. The triptolide nanoparticles were characterized by TEM and AFM at the same time. It was found that the structure of the nanoparticles was round and the surface was smooth. <\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>References:<\/p><p> 1. Shiraishi K, Endoh R, Furuhata H, et al. A facile preparation method of a PFC-containing nano -sized emulsion for theranostics of solid tumors. <em>Int J Pharm, <\/em>2011, 421: 379-387.<br> 2. HaoL, Wang X, Zhang D, et al. Studies on the preparation. characterizaion and pharmacokinetics of amoitone b .nanocrystals. <em>Int J Pharm<\/em>, 2012, 433: 157-164. .<br> 3. QiC, Chen Y, Huang\u300d, et al. Preparation and characterization of catalase-loaded solid lipid nanoparticles based on soybean phosphatidylcholine. <em>J Sci Food Agric<\/em>, 2012, 92: 787-793.<br> 4. Yoshizawa T, Hattori Y\uff0cHakoshima M\uff0cet al. Folate linked lipid- based nanoparticles for synthetic sirna delivery in kb tumor xenografts. <em>Eur J Pharm Biopharm<\/em>, 2008, 70; 718-725. <\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Particle size is an important detection index for nano-pharmaceutical preparations. All nano-pharmaceutical preparations must be tested for particle size and<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[14,5],"class_list":["post-71","post","type-post","status-publish","format-standard","hentry","category-nanoparticles","tag-characterization-techniques","tag-nanoparticles"],"_links":{"self":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/71","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/comments?post=71"}],"version-history":[{"count":1,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/71\/revisions"}],"predecessor-version":[{"id":74,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/71\/revisions\/74"}],"wp:attachment":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/media?parent=71"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/categories?post=71"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/tags?post=71"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}