The Synthesis Of Cyclodextrin-Modified Magnetic Nanoparticles

Cyclodextrins(CDs) play major roles in many disciplines such as supramolecular chemistry,analytical chemistry,catalysis and biomedicine. Since their discovery,the parent CDs and their derivatives have served as multi-purpose prototypes for novel host compounds.Properly sized and shaped guests can enter the cavity to form inclusion complexes that can be stabilized by hydrophobic interactions,van der Waals forces and hydrogen bonds.All these properties account for their aqueous solubility and ability to encapsulate hydrophobic moieties into their cavities.This has been the basis for their analytical and biomedical applications.Nanoscience is a very important research and development frontier in modern science.Magnetic particle is a class of popular materials among the spherical nanoparticles and has been increasingly used in immobilizing proteins,enzymes,and other bioactive agents in analytical biochemistry, medicine,and biotechnology.The special feature of magnetic crystals is their prompt response to a remote magnetic force.Because superparamagnetic nanocrystals do not retain magnetism after the removal of the external magnetic field,they(Fe₃O₄ nanoparticles,especially) have been extensively exploited as the materials of choice for contrast enhancement in magnetic resonance imaging(MRI),labeling and sorting of cells,hyperthermia treatment for malignant cells and separation of biochemical products.Our ultimate goal is to construct a practical targeted drug delivery system via layer-by-layer method by whichβ-CD's hydrophobic cavity is combined with SiO₂-coated superparamagnetic Fe₃O₄(Fe₃O₄/SiO₂) nanoparticles.The two moieties emerge into one nano-system to afford a novel multi-purpose material that can act as a promising candidate drug carrier and bioseparator for biomedical application.This dissertation consists of four chapters:Chapter 1:Introduction.This part presents general introduction of cyclodextrins,magnetic nanoparticles' related concepts and their applications.Chapter 2:Synthesis of cyclodextrin derivative.6-TsO-β-CD was synthesized via a relatively eco-friendly method.The products were characterized by ¹H NMR.Chapter 3:The synthesis of magnetite nanoparticles and their cyclodextin-functionalization.The work synthesized superparamagnetic magnetite nanoparticles via coprecipitaion method.Then,hydrolysis of APTES formed a layer of -NH₂ functionalized silane coating.Finally, 6-TsO-β-CD was grafted onto the surface of the magnetic nanoparticles. The reactions were monitored by XRD,FT-IR,TEM,TGA and VSM.