the present invention relates to biocompatible and biodegradable , stimuli sensitive , polymeric nanoparticles , which are formed by ion - ion interaction in aqueous media . synthetic and biological macromolecules with ionizable functional groups are capable of forming nanoparticles whose size and surface properties are sensitive to environmental factors such as ph , temperature and salt concentration . nanodevices made from these nanoparticles are designed for therapeutic applications included but not limited to use as drug carriers and / or used as contrast agents in mri diagnosis and the like . the adjustable size of the nanodevices and their stimuli sensitivity allows specific delivery applications . thus , these nanosystems are potential carrier tools for delivery of active ingredients such as drugs , as well as dna , rna , sirna for cosmetics , pharmaceutical applications , etc .