Gold nanoparticles as novel agents for cancer therapy

Abstract

Gold nanoparticles are emerging as promising agents for cancer therapy and are being investigated as drug carriers, photothermal agents, contrast agents and radiosensitisers. This review introduces the field of nanotechnology with a focus on recent gold nanoparticle research which has led to early-phase clinical trials. In particular, the pre-clinical evidence for gold nanoparticles as sensitisers with ionising radiation in vitro and in vivo at kilovoltage and megavoltage energies is discussed.

Figure 1

Number of gold nanoparticle papers published each year. Source: ISI Web of Knowledge. Available from: www.webofknowledge.com.

Figure 2

Absorption spectra of 9-nm, 22-nm, 48-nm and 99-nm gold nanoparticles demonstrating a change in surface plasmon resonance with particle diameter. Reproduced with permission from Link et al [87].

Figure 3

Tumour growth of human prostate cancer tumours in mice. C, control; GNS, gold nanoshells; L, laser; S, sham treated. Reproduced with permission from Stern et al [40].

Figure 4

The relationship of mass attenuation coefficients of soft tissue and gold with increasing photon energy (source: National Institute Standards and Technologies).

Figure 5

The influence of the free radical scavenger tris(hydroxymethyl)aminomethane on DNA plasmid-bound gold nanoparticle (GNP) radiosensitisation. Enhancement increases with concentration as more water radicals are scavenged. At concentrations >100 mM, enhancement falls as GNP-produced radicals are also scavenged. Reproduced with permission from Carter et al [57].

Figure 6

Triangles: tumour growth after no treatment (n=12); diamonds: gold only (n=4); circles: radiation only (30 Gy, n=11); squares: gold and radiation (n=10). Reproduced with permission from Hainfeld et al [26].

Figure 7

Kaplan–Meier survival. Circles: no treatment or gold alone; triangles: radiation only; squares: radiation after 1.35 g of Au kg^–1 gold nanoparticles; diamonds: radiation after of 2.7 g of Au kg^–1 injection. Reproduced with permission from Hainfeld et al [26].