Study of porous magnetic nanocomposites for bio-catalysis and drug delivery

Despite advances in diagnostic procedures and treatments, the overall survival rate from cancer has not improved substantially over the past 30 years. One promising development is the encapsulation of toxic cancer chemotherapeutic reagents within biocompatible nanocomposite materials. The targeted stimuli triggered drug release restrict the toxic drugs to the tumour site, thereby reducing the effects of “free drug” on healthy tissues. One of the most versatile and safe materials used in medicine are iron oxide nanoparticles. This project describes the development of several formulations based on magnetite nanoparticles for drug delivery applications. Utilising magnetic nanoparticles in drug delivery systems allowed for the synergistic effects of hyperthermia and heat triggered drug released. The drug delivery systems developed in this project include magnetoliposomes, magnetic micelles, mesoporous silica-magnetite core-shell nanoparticles, liposome capped mesoporous silica-magnetite core-shell nanoparticles (protocells) and polymer capped mesoporous silica-magnetite core-shell nanoparticles. The drug loading and release profiles of the developed nanomaterials were assessed using two different anticancer drugs; Mitomycin C (MMC) and Doxorubicin (DOX). The drug loading content and drug loading efficiency for different nanocomposites ranged from 0.48 to 10.30% and 16.16 to 85.85%, respectively. Drug release profiles were studied in vitro at 37°C at pH 5.5 and pH 7.4 and at hyperthermia elevated temperature of 43°C to evaluate the effects of pH and temperature on the release profiles. An AC magnetic field with frequency of 406 kHz and variable field of up to 200 G was used to induce magnetic heating and keep the temperature within hyperthermia treatment range. Compared to uncapped mesoporous silica nanoparticles capping the mesopores of the silica nanoparticles with liposome or polymer reduced the drug release by 52.7% and 41.5%, respectively. The efficacy of doxorubicin-containing nanoparticles were evaluated in ...