Figure 4.

Nanoparticles used for gene delivery. Examples of metallic nanoparticles are gold nanoparticles (AuNPs) that can be functionalized with several molecules, e.g., short hairpin RNA (shRNA) for gene silencing. Other examples of inorganic nanoparticles are superparamagnetic iron oxide nanoparticles (SPION) containing an iron core coated with biocompatible polymers, mesoporous silica nanoparticles or carbon nanotubes. Examples of organic nanoparticles are polymeric nanoparticles, and liposomes and solid lipid nanoparticles (SLNs), which are lipid-base nanoparticles that differ mainly in the aqueous and lipidic core and the number of lipid layers. Exosomes are nanovesicles secreted by eukaryotic cells composed by a bi-lipidic membrane containing membrane proteins, that surround an aqueous lumen containing proteins and nucleic acids.