Gold nanoparticles are widely used in medical diagnostics and treatment due to their unique optical and electronic properties. They serve as effective contrast agents in imaging techniques, enhancing the clarity of X-rays, CT scans, and other diagnostic tools. In cancer therapy, these nanoparticles are employed in targeted drug delivery systems, where they attach to cancer cells and release therapeutic agents directly into the tumor, minimizing damage to healthy tissues. Additionally, their ability to convert light into heat makes them valuable in photothermal therapy, where they are used to destroy cancer cells through localized heating. In the field of biosensors, gold nanoparticles are utilized for their high sensitivity in detecting biomolecules, aiding in the early diagnosis of diseases. They are also integral in environmental monitoring, where they help detect pollutants and toxins in water and air.

Furthermore, their application in electronics includes the development of conductive inks and coatings, enhancing the performance of various electronic devices, as well as in the production of sensors and small-scale electronics due to their excellent conductivity and stability.

In cosmetics, gold nanoparticles are incorporated into skincare products for their antioxidant properties and ability to stimulate collagen production, aiding in skin repair and rejuvenation.

In chemical processes, they act as catalysts to improve the efficiency and speed of various reactions.