ULTRASOUND ASSISTED NON-SEEDED METHOD ON SURFACE MODIFICATION OF SUPERPARAMAGNETIC IRON OXIDE NANOPARTICLES FOR MAGNETIC RESONANCE IMAGING PROBE by BASHIRU KAYODE SODIPO A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy

............................................................................................................... XVII CHAPTER 1: INTRODUCTION ................................................................................... 1 1.1 NANOTECHNOLOGY ................................................................................................ 1 1.2 SUPERPARAMAGNETIC IRON OXIDE NANOPARTICLES ............................................. 2 1.3 BIOMEDICAL APPLICATIONS OF SPION ................................................................... 3 1.4 LIMITATIONS OF SPION AS A BIOMEDICAL PROBE ................................................. 4 1.4.1 SURFACE MODIFICATION OF SPION ................................................................... 5 1.5 PROBLEM STATEMENT ............................................................................................. 5 iv 1.6 AIMS AND OBJECTIVES............................................................................................ 6 1.7 THESIS OUTLINE ..................................................................................................... 7 CHAPTER 2: LITERATURE REVIEW ....................................................................... 9 2.1 MAGNETITE............................................................................................................. 9 2.2 MAGHEMITE ............................................................................................................ 9 2.3 MAGNETIC PROPERTY OF SPION .......................................................................... 10 2.4 SYNTHESIS OF SPION ........................................................................................... 12 I. Co-precipitation Method .................................................................................. 12 II. Sol-Gel Method ................................................................................................ 14 III. Microemulsion Method .................................................................................... 15 IV. Hydrothermal Method ...................................................................................... 16 V. Solvothermal Method ....................................................................................... 17 VI. Sonochemical Method ...................................................................................... 17 VII. Electrochemical Method .................................................................................. 18 2.5 SURFACE MODIFICATION OF SPION WITH SILICA NANOPARTICLES ..................... 19 2.5.1 WET CHEMICAL SYNTHESIS OF SILICA COATED SPION ................................... 19 v I. Sol-Gel Synthesis of Silica Coated SPION ...................................................... 19 II. Microemulsion Synthesis of Silica Coated SPION .......................................... 20 III. Modification of Sol-Gel and Microemulsion Method ..................................... 21 IV. Magnetic Mesoporous Silica Nanoparticles .................................................... 21 2.6 SUMMARY ......................................................................................................... 22 CHAPTER 3: THEORY................................................................................................ 23 3.1 THEORY OF SONOCHEMISTRY ............................................................................... 23 3.2 EFFECTS OF ACOUSTIC CAVITATION ..................................................................... 26 3.2.1 PHYSICAL EFFECTS ........................................................................................... 26 3.2.2 CHEMICAL EFFECTS .......................................................................................... 28 3.3 THEORY OF MAGNETIC RESONANCE IMAGING (MRI) ........................................... 28 3.4 T1 RELAXATION TIME .......................................................................................... 32 3.5 T2 RELAXATION TIME .......................................................................................... 33 3.6 MRI CONTRAST AGENT ........................................................................................ 34 3.7 SUMMARY ............................................................................................................. 35