Nanoparticles are small particles that range between 1 to 100 nanometers in size. They are objects of study in many sciences such as chemistry, physics, geology, and biology, and occur widely in nature. Nanoparticles are an important component of atmospheric pollution and key ingredients in many industrialized products such as paints, plastics, metals, ceramics, and magnetic products. The production of nanoparticles with specific properties is a branch of nanotechnology.
Nanoparticles can exhibit significantly different physical and chemical properties compared to their larger material counterparts due to their very small size. Most nanoparticles are made up of only a few hundred atoms. The material properties change as their size approaches the atomic scale, resulting in the material’s surface atoms dominating the material performance.
The definition given by the European Commission states that the particle size of at least half of the particles in the number size distribution must measure 100 nm or below. According to the International Standards Organization (ISO) technical specification 80004, a nanoparticle is an object with all three external dimensions in the nanoscale, whose longest and shortest axes do not differ significantly, with a significant difference typically being a factor of at least 3.
Nanoparticles have emerged as important players in modern medicine, with potential applications in drug delivery, imaging, and diagnostics. However, they also have potential toxicities that need to be studied and addressed.
