A nanoshell is a 100 nanometer spherical shell of metal (often gold) surrounding a core of silicon dioxide atoms. Naomi Halas, a professor at Rice University, is the inventor of the nanoshell. Nanoshells have special optical properties with various promising applications; these applications are primarily being investigated at Rice University. Nanoshells are currently being investigated as:
- a treatment for cancer similar to chemotherapy but without the toxic side-effects
- inexpensive, quick analysis of “samples as small as a single molecule” and builds on Raman spectroscopy

Nanoshells featured in the fictional Alex Rider book Scorpia, where they were filled with cyanide to kill thousands.