Introduction

A nanoparticle is an extremely small particle, measuring between 1 and 100 nanometres. To give you an idea, a nanometre is one billionth of a metre. If you were to cut a single human hair into 100,000 pieces, one of those fragments would be roughly the size of a nanoparticle (TWI Global, 2023).

At this microscopic scale, materials often behave very differently from their larger, bulkier forms. For example, gold, which normally appears shiny and yellow, can appear red or purple when reduced to nanoparticles due to the way it interacts with light. Nanoparticles also have a very high surface-to-volume ratio, making them much more reactive and useful for chemical, biological, and technological applications (PNNL, 2023)

In medicine, nanoparticles are particularly important. They act as microscopic transport vehicles for drugs. Scientists can design them to:

• travel safely through the bloodstream,
• avoid destruction by the immune system,
• attach specifically to diseased cells (such as cancer cells), and
• release drugs in a controlled manner only at the site of the disease.

This ability to deliver treatments with such precision is why nanoparticles are fundamental to nanomedicine. For example, lipid nanoparticles have been essential for transporting the fragile mRNA used in COVID-19 vaccines. Similarly, researchers are testing nanoparticles that can cross the blood-brain barrier, opening new doors for the treatment of neurological diseases (NIH, 2022).