Gold Nanoparticles in Biomedical Applications

Lev Dykman, Nikolai Khlebtsov

• Publisher: CRC Press
• Year: 2017
• eBook ISBN: 9781351360470
• Topic: Medicine
• Subtopic: Biotechnology in Medicine

This book discusses fabrication of functionalized gold nanoparticles (GNPs) and multifunctional nanocomposites, their optical properties, and applications in biological studies. This is the very first book of its kind to comprehensively discuss published data on in vitro and in vivo biodistribution, toxicity, and uptake of GNP by mammalian cells providing a systematization of data over the GNP types and parameters, their surface functionalization, animal and cell models. As distinct from other related books, Gold Nanoparticles in Biomedical Applications discusses the immunological properties of GNPs and summarizes their applications as an antigen carrier and adjuvant in immunization for the preparation of antibodies in vivo. Although the potential of GNPs in nanobiotechnology has been recognized for the past decade, new insights into the unique properties of multifunctional nanostructures have recently emerged. With these developments in mind, this book unites ground breaking experimental data with a discussion of hybrid nanoparticle systems that combine different nanomaterials to create multifunctional structures. These novel hybrids constitute the material basis of theranostics, bringing together the advanced properties of functionalized GNPs and composites into a single multifunctional nanostructure with simultaneous diagnostic and therapeutic functions. Such nanohybrids can be physically and chemically tailored for a particular organ, disease, and patient thus making personalized medicine available.

1Optical Properties of Gold Nanoparticles

1.1Chemical Wet Synthesis of Gold Nanoparticles

Methods of synthesis of colloidal gold (CG) (and other metal colloids) can be arbitrarily divided into the following two large groups: dispersion methods (metal dispersion) and condensation methods (reduction of the corresponding metal salts).

Dispersion methods for the preparation of CG are based on destruction of the crystal lattice of metallic gold in high-voltage electric field [1] or laser ablation [2]. If an electric arc is created in a liquid between two gold electrodes under electric field, its blazing leads to the mass transfer between electrodes accompanied by CG formation. The yield and shape of gold particles formed under electric current depend not only on the voltage between electrodes and the current strength but also on the presence of electrolytes in solution. The use of direct current leads to the formation of nonuniform gold particles. The addition of even very small amounts of alkalis or chlorides and the use of high-frequency alternating current for dispersion substantially improve the quality of gold hydrosols.

Condensation methods are more commonly employed than dispersion methods. CG is most often prepared by reduction of gold halides (for example, of HAuCl4) with the use of chemical reducing agents and/or irradiation (ultrasonic and ultraviolet [UV] irradiation, pulse or laser radiolysis). Various organic and inorganic compounds (more than 100) serve as chemical reducing agents. At present, the most popular colloidal synthesis protocols involve the citrate reduction of HAuCl4, as suggested by Borowskaja [3], Turkevich et al. [4], and Frens [5], to produce relatively monodisperse particles with controlled average equivolume diameters of 10 to 100 nm. For smaller particles, other reducing agents can be used, e.g., a mixture of borohydride and ethylenediaminetetra acetic acid (EDTA) [6] (5 nm) or sodium or potassium thiocyanate [7] (1 to 2 nm). The shape of particles larger than 100 nm can be improved by the method described by Goia and Matijević [8]. A sol with a narrow Au particle size distribution can be prepared by adding presynthesized Au seeds, on which condensation will occur, to an HAuCl4 solution. In this method, sodium citrate or hydroxylamine can serve as reducing agents [9]. Isodisperse and isomorphous sols can be prepared only if the formation of new nuclei is prevented. As a rule, it is achieved by performing the process in two steps. Initially, a new phase nucleates, and then weak supersaturation is created in the sol, due to which new nuclei are not produced any more and only the already formed nuclei grow [10].

Despite more than half a century of study and application recovery citrate HAuCl4, the chemistry of the reaction and the process of formation and development of gold particles continues to interest researchers [11–18].

Gold nanoparticles (GNPs) can also be prepared by the two-phase microemulsion method. In the...

Table of contents

• Cover
• Half Title Page
• Title Page
• Copyright Page
• Contents
• Preface
• Author
• Introduction
• Chapter 1 Optical Properties of Gold Nanoparticles
• Chapter 2 Gold Nanoparticles in Biology and Medicine
• Chapter 3 Biodistribution and Toxicity of Gold Nanoparticles
• Chapter 4 Uptake of Gold Nanoparticles into Mammalian Cells
• Chapter 5 Immunological Properties of Gold Nanoparticles
• Chapter 6 Multifunctional Gold-Based Composites for Theranostics
• Index