Nanogold as a component of active drugs and diagnostic agents

Nanotechnology is a fast-growing field of science that dates back to the late 1950s. Nanoparticles can be divided into organic, inorganic, and carbon-based. An example of inorganic nanoparticles, in which relatively high hopes for the development of both pharmacy and medicine are placed, are gold nanoparticles. They possess beneficial properties, such as small size (ranging from several to several hundred nanometers), a large specific surface area to volume, and characteristic optical properties, as well they are relatively easy to synthesize with the ability to control the parameters of the final product to obtain desired sizes and shapes. Moreover, they exhibit high biocompatibility and low toxicity, which is especially important when administered internally (per os, i. v.). Several methods for the synthesis of gold nanoparticles (AuNPs) have been described in the literature, including chemical, physical, and biological methods. Microorganisms such as fungi, plants, and algae are used to produce gold nanoparticles. Due to their particle size and ability to penetrate cell membranes, gold nanoparticles are being considered as drug carriers. Many attempts have been made to attach gold nanoparticles to drugs, focusing mainly on antimicrobial and anticancer drugs. Treatment with these drugs in combination with nanoparticles is more effective than applying free drugs without the carrier. AuNPs have also been used with great success in the photothermal therapy of cancer. Additionally, work is underway to use them in diagnostics to prepare flow assays, increasing the sensitivity and specificity of the tests. Due to a large amount of scientific data on nanogold, this review focuses on presenting methods for obtaining gold nanoparticles and approximating their applications in areas of medical science.