Nanoparticles, which are luminescent and/or electroactive and/or suitable for MRI (magnetic resonance imaging and/or PET (positron emission tomography) applications, comprise a micelle, which has a hydrophilic shell and an hydrophobic central portion, and a polysilicate core; the micelle comprises a plurality of molecules of a functionalized surfactant having the following structure: M1-Hydro1-Lipo-Hydro2-M2 wherein Lipo indicates a hydrophobic chain; Hydro1 ed Hydro2 indicate, each, a respective hydrophilic chain; M1 ed M2 represent respective recognition functionalities.