nanoparticles for targeting and multi-stimuli responsive nano drug delivery application

various polymeric nanoparticles (nps) with optimal size, tumor-targeting functionalization, or microenvironment sensitive characteristics have been designed to solve several limitations of conventional chemotherapy. nano-sized polymeric drug carrier systems have remarkably great advantages in drug delivery and cancer therapy, which are still plagued with severe deficiencies, especially insufficient cellular uptake. therapeutic nanoparticle (np) technologies have the potential to revolutionize the drug development process and change the landscape of the pharmaceutical industry. by virtue of their unique physicochemical properties, nanoparticles have shown promise in delivering a range of molecules to desired sites in the body.nanoparticle technologies may improve the therapeutic index of drugs by enhancing their efficacy and/or increasing their tolerability in the body. nanoparticles could also improve the bioavailability of water-insoluble drugs, carry large payloads,protect the therapeutic agents from physiological barriers, as well as enable the development of novel classes of bioactive macromolecules (e.g., dna and sirna).additionally, the incorporation of imaging contrast agents within nanoparticles can allow us to visualize the site of drug delivery or monitor the in vivo effi cacy of the therapeutic agent. thus far, over two-dozen nanotechnology products have been approved by the us food and drug administration (fda) for clinical use, and many are under clinic and preclinic development. interestingly, the majority of these clinically approved, fi rst-generation nanotechnology products are comprised of liposomal drugs and polymer–drug conjugates, which are relatively simple and generally lack active targeting or controlled drug release components.to develop safer and more effective therapeutic nanoparticles, researchers have designed novel multifunctional nanoparticle platforms for cell/tissue-specifi c targeting, sustained or triggered drug delivery, co-delivery of synergistic drug combinations, etc. among these functions, we believe that spatial and temporal controls in drug delivery may be critical for the successful development of next-generation nanotechnology products.