spherical or capsule-shaped structure. Most, though not all, nanoparticles
are hollow, which provides a central reservoir that can be filled with
anticancer drugs, detection agents, or chemicals, known as reporters, that
can signal if a drug is having a therapeutic effect. The surface of a
nanoparticle can also be adorned with various targeting agents, such as
antibodies, drugs, imaging agents, and reporters. Most nanoparticles are
constructed to be small enough to pass through blood capillaries
and enter cells.