Iron oxide- Indocyanine green based magneto-optical nanocomposites for potential multi-modal applications in cancer therapeutics

Magneto-optical nanocomposites possess properties of both magnetic and optical components as novel nanomedicines and demonstrate an immense potential in cancer therapeutics under the application of external stimuli such as alternating magnetic field (AMF) and near-infrared (NIR) laser irradiation. In this thesis, two different hydrophilic and one hydrophobic iron oxide nanoparticles (IONPs) types synthesised by modified co-precipitation methods, acted as a magnetic component. Synthesised IONPs cores (IO1, IO2 and IO3) were further coated with mesoporous silica shell using hexadecyl trimethyl ammonium bromide (CTAB) as a surface directing agent. Upon removal of CTAB from the mesopores by acidic ethanolic washing, the resultant magnetic silica (MS) nanocomposites (MS1, MS2 and MS3) were utilised for loading indocyanine green (ICG), acting as an optical component. The resultant ICG loaded magnetic silica nanocomposites (MSICG) nanocomposites (MS1ICG, MS2ICG and MS3ICG) were novel magneto-optical nanocomposites. Synthesised IONPs, MS and MSICG nanocomposites were extensively characterised and tested for their performance in magnetic hyperthermia therapy (MHT), photothermal therapy (PTT) and photodynamic therapy (PDT) in-vitro using commercial MCF7 breast cancer cell lines. All the synthesised IONPs were spherical in morphology with superparamagnetic properties. Hydrophilic IONPs (IO1 and IO2) exhibited higher saturation magnetisation of 63.6 emu/g and 59.4 emu/g compared to hydrophobic IONPs (IO3) of 49.3 emu/g. Zeta potential measurements indicated that the surface of the IONPs were positively charged. The distinct XRD patterns corresponds to iron oxides. All IONPs showed a distinct Fe-O bond vibration at 550 cm-1 from FTIR analysis due to magnetite phase. In addition, hydrophobic IONPs showed peaks at 2925 and 2852 cm-1, corresponding to -CH2 stretching vibrations due to the presence of oleic acid. Following silica coating, the MS nanocomposites were nearly spherical