Applications of Gold Nanostars: Nanosensing, Thermal Therapy, Delivery Systems

Abstract

This chapter focuses on the most relevant applications of GNS in life science. The versatility of the GNS functionalization is combined with their optical properties to provide promising and prospective approaches in a variety of biomedical fi elds. Nanosensing assays, thermal treatments, and delivery systems based on GNS are discussed in this chapter. Keywords SERS-based sensing • Hyperthermia • Photothermal effect • Smart deliveryFunctionalized gold nanoparticles with controlled geometrical and optical properties are the subject of intensive studies and biomedical applications, including genomics, biosensors, immunoassays, clinical chemistry, laser phototherapy of cancer cells and tumors, and delivery platforms. In these fi elds targeted delivery of drugs, DNA, and antigens is coupled to optical bioimaging and the possibility to monitor cells and image details of tissues with the use of state-of-the-art detection systems [ 1 ]. Nonspherical gold nanoparticles are particularly interesting due to their capability to release locally heat with large effi ciency when they are irradiated in the NIR region of the spectrum [ 2 ]. In addition their size and the shape anisotropy essentially determine the position and the amplitude of the NIR-localized surface plasmon resonance [ 3 ]. The shape of the gold nanostars (GNS), in particular, can be tuned from the shape of sea urchin to that of planar, highly regular penta-branched stars [ 4 ]. The NIR-localized surface plasmon resonance of GNS can be consequently tuned in a wide NIR range up to 1250 nm by varying the axial ratio of protruding branches and multiple LSPR band in the NIR can also be obtained [ 4 ]. The possibility to easily decorate the surface of GNS, in combination with their optical properties

Synthesis and Characterization of Hyper‐Branched Nanoparticles with Magnetic and Plasmonic Properties

“…In the second step, the seeds solution (24 μL) was added to a water growth solution (21.3 mL) in which tetrachloroauric acid and Triton X-100 are mixed with a weak reducing agent (ascorbic acid) and silver nitrate. These mild reducing agents have been reported [93,94] to induce a disproportion reaction(eq.2):…”

Applications of Nanomaterials for Immunosensing

“…Gold Nanoparticles (AuNP) can be synthesized within a wide range of sizes and shapes with a multitude of surface coatings [43,47,73,74]. Moreover, they present characteristic localized surface plasmon resonance (LSPR) bands.…”

N-Methyl-2-pyrrolidone as a Reaction Medium for Gold(III)-Ion Reduction and Star-like Gold Nanostructure Formation

“…Furthermore, the effects of the PVP concentration and the presence of preformed AuNPs on the kinetic reduction of gold ions and, consequently, on the morphology and optical response of AuNS synthesized in this organic medium are discussed based on experimental and theoretical studies. The importance of controlling the properties of AuNS is better understood by considering the various applications of this structure in different fields, such as life science, sensing, thermal therapy, or drug delivery. These diverse applications are based on the optical properties and the higher enhancement factors of this structure than other morphologies for Raman spectroscopy …”