| Fullerenes and their derivatives have shown broad range of applications in many scientific areas such as biological, nonlinear optics, photoconductors, and photovoltaic due to their unique structure and properties. Especially, fullerenes have attracted considerable attention in recent years in photodynamic therapy owing to their interesting photophysical properties. The primary goal of this dissertation is to develop multi-cationic [60]fullerene-based nanomaterials as photosensitizers for the application of antimicrobial photodynamic therapy. Hence design, synthesis and characterization of novel multi-cationic [60]fullerene derivatives are the main subjects of discussion.;The first part of this dissertation includes introduction to photodynamic therapy (PDT), antimicrobial photodynamic therapy, [60]fullerene and its chemistry followed by synthesis of multi-cationic [60]fullerene derivatives and investigation of in vitro antibacterial photodynamic inactivation abilities of these materials against pathogenic Gram-positive (e.g., Staphylococcus aureus) and Gram-negative (e.g., Escherichia coli) bacteria. For the synthesis of these materials, first we have prepared multiple tertiary amines containing molecules with primary amines as end groups, N 6C4 and N6C3, via sequential protection and deprotection of hexamethylenepentamine starting material. Subsequent coupling reactions of the primary amines of obtained amines with half ester malonic acids, ME1 and ME3, followed by the quaternization of tertiary amines yielded quaternized malonamide intermediates. Upon the attachment of C60 fullerene cage to these quaternized malonamide intermediates employing Bingel reaction produced novel tetra- and penta-cationic C 60 fullerene derivatives, [C60(>ME3)]2N 6+C4), C60(>ME1N 6+C3), C60(>ME3N 6+C3). After establishing the synthetic method for above molecules, we have extended this method for the synthesis of another interesting and promising C60 fullerene derivative, using N 6C3. The primary amine of N6C3 was first reacted with lactone to yield the amide with primary alcohol as end group, C3N6C3-OH. Reaction of this alcohol with malonic acid on both sides, followed by quaternization and C60 fullerene cage attachement produced novel deca-cationic C60 fullerene derivative, C60[>M(N6+C3C 1)2]. Thus obtained fullerene derivatives along with intermediates obtained from each step were characterized by using spectroscopic methods such as nuclear magnetic resonance (NMR), infrared (FT-IR), UV-Vis spectra, and electron microscopes (TEM/SEM), In vitro antibacterial photodynamic inactivation studies were carried out using Gram-positive, Staphylococcus aureus 8325-4, and Gram-negative, Escherichia coli K12, bacteria (both wild type) with white (400-700 nm) broad-band light source.;The second part of this dissertation is focused on the synthesis of two-photon (2PA) active C60 fullerene derivatives for antimicrobial photodynamic therapy. This part begins with the introduction to two-photon photodynamic therapy followed by materials synthesis. Chiang et al. have reported 2PA activity of C60(>DPAF-OH). We have further functionalized this molecule with quaternized amine, N6+C 3, using half ester malonic acid as linker to yield 2PA active multi-cationic C60 fullerene derivative. These initial materials would provide the foundation for the future development of two-photon active multi-cationic C60 fullerene based materials for antimicrobial photodynamic therapy. |
