Dual pH- and temperature-responsive magnetic nanocomposite for controlled drug delivery

The thesis focused on the development of a nanoencapsulation technology to produce highly effective smart multifunctional nanocomposites that have potential to be employed as a multi-functional therapeutic agent for drug delivery and controlled drug release in combination with localized hyperthermia. To realize this ambitious goal, the thesis involved synthesis and characterization of smart nanohybrids made up of a superparamagnetic iron oxide core and a dual pH and temperature-responsive polymer shell, which are subsequently loaded with an anticancer drug, Doxorubicin. In fact, this dual stimuli-responsive magnetic nanocomposite offers spatial and temporal control over the release of the anticancer drug, triggered as a consequence of hyperthermia and tumour acidic pH corresponding to this mechanism: (i) the magnetic core produces heat in response to harmless alternating magnetic field (AMF), enhancing temperature of surrounding environment close to the hyperthermia therapeutic range and above Lower Critical Solution Temperature of polymer (LCST), specific temperature in which polymer exhibits phase transition behavior, (ii) heat generated is simultaneously conducted from core to the thermoresponsive polymer shell, which shrinks and triggers the fast release of the drug. Indeed, the increase of the temperature through magnetic hyperthermia performance, and the pH decreasing from 6 to 4 (due to the acidic pH of cancer cell) boost the release of the drug with controlled rate and concentration. Through this novel approach, therefore, undesirable side effects of the chemotherapeutic drug will be eliminated, and high efficiency of thermo-chemotherapy would be achieved.