{"id":13,"date":"2019-11-01T01:23:59","date_gmt":"2019-11-01T06:23:59","guid":{"rendered":"https:\/\/www.cd-bioparticles.com\/blog\/?p=13"},"modified":"2019-11-01T01:23:59","modified_gmt":"2019-11-01T06:23:59","slug":"gold-nanoparticles-and-their-applications","status":"publish","type":"post","link":"https:\/\/www.cd-bioparticles.com\/blog\/nanoparticles\/gold-nanoparticles-and-their-applications\/","title":{"rendered":"Gold Nanoparticles and Their Applications"},"content":{"rendered":"\n

Nanomaterials<\/strong><\/p>\n\n\n\n

Recent research shows that the application of nanomaterials\nplays an important role in the advancement of nanoscience and nanotechnology.\nNanostructured materials have a wealth of physical and chemical properties\ncompared to other small or bulk materials. Nanoparticles<\/a> have unique\nintrinsic reactivity due to their increased surface area and are ideal for the\nsynthesis of therapeutic drugs. The interaction between nanomaterials and\nbiological systems depends on the type of surface functional groups of the\nnanoparticles, particle size, particle shape, and aggregation state, as well as\ncell type, uptake pathway, and targeting organelles. Among different types of\nnanomaterials, metal nanoparticles, especially gold nanoparticles (AuNPs), have\nattracted great interest from researchers in different scientific fields due to\ntheir unique properties. Since the beginning of the 20th century, scientists\nhave done a lot of research on the existence of anisotropic gold nanoparticles,\nand found that the structure, optical properties, electronic properties,\nmagnetic properties and catalytic properties of anisotropic gold nanoparticles\nare different from those of spherical gold nanoparticles, and are generally\nsuperior to spherical gold nanoparticles.<\/p>\n\n\n\n

Advantages of gold nanoparticles<\/strong><\/p>\n\n\n\n

1) The X-ray absorption coefficient is high;<\/p>\n\n\n\n

2) Simple synthesis operation;<\/p>\n\n\n\n

3) Physicochemical properties of particles that can be\nprecisely controlled;<\/p>\n\n\n\n

4) Strong binding affinity for mercaptans, disulfides, and amines;<\/p>\n\n\n\n

5) Unique adjustable optical and electronic properties;<\/p>\n\n\n\n

6) Widely used in nanoelectronics, optoelectronics, catalysis, and biomedical applications.<\/p>\n\n\n\n

Classification of gold nanoparticles<\/strong><\/p>\n\n\n\n

According to the size, AuNPs can be divided into four\ncategories (Figure 1):<\/p>\n\n\n\n

Figure 1. Transmission electron micrograph (a-f) and scanning electron micrograph (g-h) of gold nanoparticles. (Yamal, G., et al. 2013; Xu, X., et al. 2013; Xiao, Y., et al. 2012; Wu, HL, et al. 2011; Wu, HY, et al. 2005; Wen , W., et al. 2016) <\/figcaption><\/figure><\/div>\n\n\n\n
1) Zero-dimensional gold nanoparticles: quantum dots,\nspherical nanoparticles (Fig. 1a);<\/p>\n\n\n\n
2) One-dimensional gold nanoparticles: nanorods (Fig. 1b),\nnanowires (Fig. 1e), nanotubes, nanobelts;<\/p>\n\n\n\n
3) Two-dimensional gold nanoparticles: nanostars (Fig. 1f),\nnanodisks;<\/p>\n\n\n\n
4) Three-dimensional gold nanoparticles: triangular\nnanoprisms (Fig. 1d), nanodumbbells (Fig. 1c), nanodendrites (Fig. 1g),\nnanocubes (Fig. 1h).<\/p>\n\n\n\n
**Application of gold nanoparticles<\/strong><\/p>\n\n\n\n**
Photodynamic therapy<\/li><\/ul>\n\n\n\n
Photodynamic therapy (PDT) is considered to be an important\ntreatment for tumor diseases and certain skin or infectious diseases, using\nphotosensitizers as light-sensitizing agents and a laser (wavelengths related\nto dye absorption peaks). Singlet oxygen and high activity free radicals\nproduced by photosensitizer energy induce tumor cell apoptosis or necrosis. In\naddition, gold nanoconjugates are easy to combine with thiols, disulfides, and\namines to promote intracellular penetration.<\/p>\n\n\n\n
Photothermal therapy<\/li><\/ul>\n\n\n\n
Photothermia (PTT), also known as thermal ablation or optical hyperthermia, is a minimally invasive, widely used method of cancer treatment. Gold nanoparticles<\/a> have a maximum absorption peak in the visible or near-infrared region and can receive light and generate heat. High temperatures can lead to the death of malignant tumors. Spherical solid gold nanoparticles larger than 50 nm in diameter are more common in photothermal therapy due to strong absorption in the near-infrared region. In addition, gold nanoparticle-antibody conjugates are also useful in diagnostic and photothermographic therapies. Like photodynamic therapy, the strong binding properties of gold nanoparticles play a key role in their intracellular transfer.<\/p>\n\n\n\n
X-ray imaging<\/li><\/ul>\n\n\n\n
As an X-ray contrast agent, gold nanoparticles have\nattracted extensive attention due to their high X-ray absorption coefficient\nand easy synthesis operation, and non-toxicity and surface functionalization.\nCommon angiographic agents such as iodinated molecules have a low molecular\nweight. Although these iodinated aromatic compounds have high water solubility\nand low toxicity characteristics, they possess short blood circulation time and\nare quickly excreted through the kidneys. Therefore, multiple injections of\niodinated aromatic compounds are required, which may cause a risk of thyroid\ndysfunction. Compared to common agents, gold nanoparticles have longer vascular\nretention time, making them suitable for imaging applications.<\/p>\n\n\n\n
Drug delivery<\/li><\/ul>\n\n\n\n
As mentioned earlier, gold nanoparticles have many\nadvantages, such as unique optical and physicochemical properties, high\nbiocompatibility, functional flexibility, adjustable monolayer, controlled\ndispersion, high surface area for loading drugs, nontoxicity and stability,\nwhich makes them an effective nanocarrier in drug delivery systems (DDSs).\nThese highly efficient nanocarriers are capable of delivering a variety of\ndrugs such as peptides, proteins, plasmid DNA (pDNA), small interfering RNA\n(siRNA) and chemotherapeutic agents. In addition to spherical gold\nnanoparticles, researchers have recently synthesized stable colloidal gold nanorods<\/a> as suitable\ncarriers for drug delivery. PEGylated gold nanorods prevent the scavenging\neffects of the reticuloendothelial system (RES), providing an efficient means\nof drug delivery. Another nanocarrier is a gold nanocage. Targeted drug\ndelivery is achieved by binding cancer cell receptors to the surface of\nnanocages surface conjugated with biologically active molecules such as\nantibodies. Gold nanorods are suitable drug delivery vehicles that benefit from\ntheir ability to utilize surface plasmon resonance to convert incident light\nenergy into thermal energy, which is the basis for targeted drug delivery\napplications for phototherapy combined with cancer therapy.<\/p>\n\n\n\n
Sensing<\/li><\/ul>\n\n\n\n
One of the main applications of gold nanoparticles is\nchemical and biological sensing. They have been used as effective sensors for\ndetecting different analytes, such as metal ions, anions, sugars, nucleotides,\nproteins and toxins. According to the sensing strategy, the gold nanoparticle\nsensor has various principles and different types of nanobiosensors utilize\ndifferent characteristics of gold nanoparticles. For example, the basic\nprinciple of colorimetric sensors is based on the visible color change caused\nby the aggregation of gold nanoparticles (Fig. 2). The fluorescence sensor\nutilizes the fluorescence quenching characteristics of gold nanoparticles; the\nelectrical and electrochemical sensors utilize the conductivity of gold\nnanoparticles, and their high surface area and catalytic properties; gold\nnanoparticle-based surface plasmon resonance sensors utilize the optical\nproperties of gold nanoparticles; and gold nanoparticle-based bio-barcode assay\nuses the strong binding affinity of gold nanoparticles to thiol and the visible\ncolor change caused by the aggregation of gold nanoparticles to achieve\ndetection purposes.<\/p>\n\n\n\n
$\"\"$
Figure 2. Optical properties of gold nanoparticles of different shapes and sizes. a) gold nanorods, b) silica-gold core-shell nanoparticles. (Xiong, W, et al. 2014) <\/figcaption><\/figure><\/div>\n\n\n\n
References\uff1a<\/p>
1. Elahi, N., Kamali, M., & Baghersad, M. H. (2018). Recent biomedical applications of gold nanoparticles: A review. *Talanta<\/em>, 184, 537-556.<\/p>*
2. Yamal, G., Sharmila, P., Rao, K. S., & Pardha-Saradhi, P. (2013). Yeast Extract Mannitol medium and its constituents promote synthesis of Au nanoparticles. *Process Biochemistry<\/em>, 48(3), 532-538.<\/p>*
3. Xu, X., Liu, X., Li, Y., & Ying, Y. (2013). A simple and rapid optical biosensor for detection of aflatoxin B1 based on competitive dispersion of gold nanorods. *Biosensors and Bioelectronics<\/em>, 47, 361-367.<\/p>*
4. Xiao, Y., Hong, H., Matson, V. Z., Javadi, A., Xu, W., Yang, Y., … & Steeber, D. A. (2012). Gold nanorods conjugated with doxorubicin and cRGD for combined anticancer drug delivery and PET imaging. *Theranostics<\/em>, 2(8), 757.<\/p>*
5. Wu, H. L., Tsai, H. R., Hung, Y. T., Lao, K. U., Liao, C. W., Chung, P. J., … & Huang, M. H. (2011). A comparative study of gold nanocubes, octahedra, and rhombic dodecahedra as highly sensitive SERS substrates. *Inorganic chemistry<\/em>, 50(17), 8106-8111.<\/p>*
6. Wu, H. Y., Chu, H. C., Kuo, T. J., Kuo, C. L., & Huang, M. H. (2005). Seed-mediated synthesis of high aspect ratio gold nanorods with nitric acid. *Chemistry of materials<\/em>, 17(25), 6447-6451.<\/p>*
7. Wen, W., Huang, J. Y., Bao, T., Zhou, J., Xia, H. X., Zhang, X. H., … & Zhao, Y. D. (2016). Increased electrocatalyzed performance through hairpin oligonucleotide aptamer-functionalized gold nanorods labels and graphene-streptavidin nanomatrix: Highly selective and sensitive electrochemical biosensor of carcinoembryonic antigen. *Biosensors and Bioelectronics<\/em>, 83, 142-148.<\/p>*
8. Xiong, W., Mazid, R., Yap, L. W., Li, X., & Cheng, W. (2014). Plasmonic caged gold nanorods for near-infrared light controlled drug delivery. *Nanoscale<\/em>, 6(23), 14388-14393.<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"*
Nanomaterials Recent research shows that the application of nanomaterials plays an important role in the advancement of nanoscience and nanotechnology.<\/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":[5],"class_list":["post-13","post","type-post","status-publish","format-standard","hentry","category-nanoparticles","tag-nanoparticles"],"_links":{"self":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/13","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=13"}],"version-history":[{"count":3,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/13\/revisions"}],"predecessor-version":[{"id":32,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/13\/revisions\/32"}],"wp:attachment":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/media?parent=13"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/categories?post=13"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/tags?post=13"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}