nanoparticle

Syllable breakdown

Dictionary meaning

a particle with at least one dimension in the size range of 1 to 100 nanometres — one nanometre being one billionth of a metre — at which scale materials exhibit physical, chemical, optical, and electronic properties that differ markedly from those of the same material in bulk form, because quantum mechanical effects and the high surface-area-to-volume ratio become dominant; the unique properties of nanoparticles — including size-tunable optical absorption, enhanced chemical reactivity, superparamagnetism, and quantum confinement effects — are exploited in applications ranging from sunscreens and cosmetics to cancer drug delivery, diagnostic imaging contrast agents, catalytic industrial processes, and electronic devices; nanoparticles are synthesised by top-down methods that break bulk material into nanoparticle size, and bottom-up methods that assemble nanoparticles from atoms and molecules

Examples

• Gold nanoparticles absorb light at wavelengths determined by their size, enabling colour-tunable optical sensors.
• Iron oxide nanoparticles guided by magnetic fields can deliver chemotherapy drugs directly to tumour tissue.