Thermoresponsive magnetic/polymer composite nanoparticles for biomedical applications

Abstract

Thermoresponsive magnetic/polymer composite nanoparticles (MPCNPs) possess unique properties for combined simultaneous application of magnetically induced targeted delivery of drugs to tumors, hyperthermia, controlled drug discharge and magnetic resonance imaging (MRI). In this regard, magnetic nanoparticles (MNPs), in particular Fe3O4 and γ-Fe2O3, are important because of their apparent biocompatibility and exclusive size-dependent qualities. Thermoresponsive polymers deliver controlled drug release, which is induced by the temperature above their lower critical solution temperature (LCST). Incorporation of MNPs into the thermoresponsive polymers structure provide combined benefits: (i) the magnetic component acts as heat source by means of magnetically assisted heating, which triggers drug release; (ii) preferential accumulation of drug loaded MPCNPs to the targeted locations is achieved by utilizing an external magnetic field; (iii) imaging and diagnostic can be done by MRI. In this article, formulation of a drug delivery system, based on ion γ-Fe2O3 MNPs and thermoresponsive polymer Poly(N-isopropylacrylamide) (PNIPAM) is presented. γ-Fe2O3 MNPs were synthesized by wet chemical method and γ-Fe2O3–PNIPAM composite nanoparticles were made by dispersion free-radical mechanism through polymerization of NIPAM. The synthesized MPCNPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo gravimetric analysis (TGA) and vibrating sample magnetometry (VSM). Anti-cancer drug, doxorubicin, was loaded into MPCNPs. The drug release profile was studied in-vitro under the influence of magnetically assisted heating conditions, when therapeutically substantial quantity of drug was released. Therefore, multimodal approach (magnetic drug targeting, simultaneous hyperthermia and controlled drug release) of cancer treatment by using anti-cancer drug loaded thermoresponsive magnetic/polymer composite nanoparticles can improve the efficacy of present cancer treatment.