Medusa particles: a magnetically triggered drug delivery system consisting of peg-pcl diblock polymer brushes bound to the surface of single crystal magnetite nanoparticles
Current cancer chemotherapy treatment involves intravenous administration of highly toxic drugs relying on the strategy that some of the chemotherapy agent will reach the site of cancer and effectively kill those cells. This method leads to mutation and damage of healthy cells, which can manifest into side effects including fatigue, alopecia, and death. To combat these side effects and to target cancer cells preferentially, we aimed to develop a drug delivery system in which chemotherapy agents, such as doxorubicin, are entrapped within a semi-crystalline polymer shell covalently attached to the surface of magnetic nanoparticles. Not only could these “medusa particles” be directed to specific sites of cancerous tissue using targeting ligands attached to an external polymer corona, but their release of drug could also be temporally controlled by a magnetically triggered thermal induction mechanism. Once the particles reach the sites of cancer, an external radio frequency alternating current magnetic field would be applied to heat the nanoparticles causing the polymer shell to melt and allowing the drug to diffuse out of the core. This mechanism could have extensive biomedical applications due to the wide variety of targeting ligands and drugs one could utilize in the drug delivery system. In this thesis, we have demonstrated synthesis of magnetite nanoparticles verified by the x-ray photoelectron spectroscopy in the Fe 2p binding energy region, and were determined to be 11 nm in diameter as seen by transmission electron microscopy. Doxorubicin was successfully loaded into medusa particles at about 2-3% by total weight on average. Magnetically triggered release of doxorubicin from medusa particles was demonstrated and monitored using UV-Vis spectroscopy, electrochemical methods including linear sweep and differential pulse voltammetry, and cell studies involving CHO-K1 cells.