 Polymer nanoparticles, N-piece, are a promising approach for drug delivery applications due to their biocompatibility and ability to target specific organs or tissues. They can be made from a variety of biocompatible synthetic polymers such as polylactic acid, PLA, polylactic co-glycolic acid, PLGA, and polyethylene glycol, PEG. These polymers are composed of simple monomers that are already found in the human body and thus do not cause any toxicity when excreted. Additionally, these polymers can be loaded with therapeutic agents such as drugs, proteins, or nucleic acids. Different methods have been developed to synthesize biocompatible N-piece, including physical encapsulation, chemical encapsulation, and electrostatic interactions. Furthermore, N-piece can be used to treat cancer and diseases affecting the central nervous system by either actively or passively targeting specific cells or crossing cellular membranes. This article was authored by Alenora Calzoni, Alessio Cesarelli, Alice Polci, and others. We are article.tv, links in the description below.