nanoparticle

A particle roughly 1 to 100 nanometres across. Nanoparticles can be made from fats, metals, polymers or ceramics, depending on the job.

In medicine they are mostly used as carriers: they package a drug or genetic material so it survives the trip through the body and reaches the right cells. In neuroscience research they are also being studied as a way to stimulate brain cells from outside the head, using magnetic fields or light that passes through the skull.

Documented real-world example: the mRNA COVID-19 vaccines from Pfizer-BioNTech and Moderna each use a lipid nanoparticle to carry the mRNA into cells.

Related terms: nanotechnology, lipid nanoparticle, magnetoelectric nanoparticles, optogenetics, blood–brain barrier

Sources: Just How Small Is Nano? — U.S. National Nanotechnology Initiative; Components of COVID-19 vaccines — Health Canada