A nanogel is a nanoparticle composed of a hydrogel -- a crosslinked hydrophilic polymer network. Nanogels are most often composed of synthetic polymers or biopolymers which are chemically or physically crosslinked. Nanogels are usually in the tens to hundreds of nanometers in diameter. Like hydrogels, the pores in nanogels can be filled with small molecules or macromolecules, and their properties, such as swelling, degradation, and chemical functionality, can be controlled.
- Nanogels composed of polyethylenimine (PEI) have been used to deliver anti-cancer compounds into cells.
- Nanogels composed of dextran have been developed for imaging tumor-associated macrophages with radionuclides and targeting the bone.
- A fluorescent nanogel thermometer was developed to measure temperatures to within 0.5°C in living cells. The cell absorbs water when colder and squeezes the water out as its internal temperature rises; the relative quantity of water masks or exposes the fluorescence of the nanogel.
Nanogels are not to be confused with Nanogel aerogel, a lightweight thermal insulator.