Nanoparticles are materials that are less than 100 nanometers in size. They differ from other nanomaterials in that all three of their dimensions are at the nanoscale. Nanoparticles have applications in areas like medical imaging, drug delivery, and tissue staining. In drug delivery, nanoparticles can be used to increase drug solubility and prolong the effects of drugs. Polymer-based nanoparticles use polymers to attach to drugs to increase solubility and uptake by cells. Liposome-based delivery uses phospholipid vesicles to encapsulate drugs and target cancer cells. Overall, nanoparticles show promise for improving drug delivery and treating conditions like cancer.