Micellar nanoparticles are composed of biocompatible block copolymers, comprising of hydrophilic polyethylene glycol (PEG) and hydrophobic polyamino acid. The formation of micelles, aggregates of 20-100 nanometer-size spheres, occurs when the block copolymers diffuse in water. Drugs and biologically active substances can be stably encapsulated in the hydrophobic inner core of the micelles. This technology can be applied to various types of compounds by modifying amino-acid side chains, etc. PEG coating on the surface ensures the micelles' stability in the bloodstream.